The origin of dolomite in Shahejie Formation shale of Jiyang Depression in eastern China were studied by means of petrologic identification, compositional analysis by X-ray diffraction, stable carbon and oxygen isotop...The origin of dolomite in Shahejie Formation shale of Jiyang Depression in eastern China were studied by means of petrologic identification, compositional analysis by X-ray diffraction, stable carbon and oxygen isotopic composition, and trace element and rare earth element analyses. The results show that the development of dolomite is limited in the lacustrine organic rich shale of Shahejie Formation in the study area. Three kinds of dolomite minerals can be identified: primary dolomite(D1), penecontemporaneous dolomite(D2), and ankerite(Ak). D1 has the structure of primary spherical dolomite, high magnesium and high calcium, with order degree of 0.3-0.5, and is characterized by the intracrystalline corrosion and coexistence of secondary enlargement along the outer edge. D2 has the characteristics of secondary enlargement, order degree of 0.5-0.7, high magnesium, high calcium and containing a little iron and manganese elements. Ak is characterized by high order degree of 0.7-0.9, rhombic crystal, high magnesium, high calcium and high iron. The micritic calcite belongs to primary origin on the basis of the carbon and oxygen isotopic compositions and the fractionation characteristics of rare earth elements. According to the oxygen isotopic fractionation equation between paragenetic dolomite and calcite, it is calculated that the formation temperature of dolomite in the shale is between 36.76-45.83 ℃, belonging to lacustrine low-temperature dolomite. Based on the maturation and growth mechanism of primary and penecontemporaneous dolomite crystals, a dolomite diagenetic sequence and the dolomitization process are proposed, which is corresponding to the diagenetic environment of Shahejie Formation shale in the study area.展开更多
It was showed that understanding of the diagenetic modifications and its associated products in the deeply to ultra-deeply buried tight sandstone reservoirs(DUDTSR)is great important for reservoir characterization and...It was showed that understanding of the diagenetic modifications and its associated products in the deeply to ultra-deeply buried tight sandstone reservoirs(DUDTSR)is great important for reservoir characterization and hydrocarbon prediction.However,the fine characterization of diagenetic evolution via geologic modelling in tight sandstones remains a great challenge as for complexity of lithology,temperature,pressure and formation fluid throughout the entire life cycle of tight sandstone reservoirs.To help get a comprehensive idea of the distribution of diagenetic processes on the formation of DUDTSR in the long geological period,type-I and type-II fine sections of diagenetic stage for clastic reservoirs were creatively proposed and its essence was illustrated using the Paleogene Huagang(EH)Formation in the southern Xihu Sag.Through combination of both quantitative and qualitative methods which began with current formation temperature,vitrinite analysis,illite and I/S mixed layers based on analytical testing of the EH Formation,(1)Paleotemperature(T),vitrinite reflectivity and smectite in mixed layer during burial processes were restored based on numerical analysis,(2)The accurate division of diagenetic evolution was identified from coarse to fine process using new model,(3)And finally the geological significance of fine division of the conventional diagenetic stage was illustrated for low-porosity and tight sandstone reservoirs.展开更多
The reservoir properties, diagenetic features and evolution of the Paleogene Shahejie Formation(Es) in the Nanpu sag, Bohai Bay Basin were analyzed based on mineralogical and petrological data, and the main controllin...The reservoir properties, diagenetic features and evolution of the Paleogene Shahejie Formation(Es) in the Nanpu sag, Bohai Bay Basin were analyzed based on mineralogical and petrological data, and the main controlling factors and formation mechanisms of medium to deep high-quality reservoir were revealed by multiple regression analysis. The results show that the sedimentary microfacies, rigid grains content, and dissolution process are the key factors controlling the formation of high-quality clastic reservoir in middle to deep depth in the Nanpu sag. The formation mechanisms of middle to deep sandstones of the Es in different structural belts differ widely in formation mechanism. The Es1(uppermost member of Es) sandstone reservoirs in the Nanpu No.3 structural belt is low porosity, moderate to high permeability reservoir in the mesodiagenesis A2 stage on the whole, and the formation of high-quality reservoirs is mainly attributed to strong compaction resistance ability primarily, and dissolution process secondarily. The Es3(third member of Es) sandstones in Gaoshangpu structural belt is classified as tight sandstones in the mesodiagenesis A1 stage, in which the development of favorable reservoirs is primarily controlled by dissolution. This study provides references for reservoir evaluation of deep clastic reservoirs and exploration deployment in the Bohai Bay rift basin. As there are high-quality reservoirs, it is believed that the deep clastic reservoirs in the eastern of China, such as Bohai Bay Basin still have significant exploration potential.展开更多
Petrographic analysis combined with various techniques, such as thin section identification, fluid inclusions, isotopic data, petro-physical property testing and oil testing results, was used to study diagenetic evolu...Petrographic analysis combined with various techniques, such as thin section identification, fluid inclusions, isotopic data, petro-physical property testing and oil testing results, was used to study diagenetic evolution and its effect on reservoir-quality of fan delta reservoirs of Es4s in the Bonan sag. The diagenesis is principally characterized by strong compaction, undercompaction, multi-phase of dissolution and cementation. Compaction played a more important role than cementation in destroying the primary porosity of the sandstones. The reservoirs have experienced complicated diagenetic environment evolution of "weak alkalineacid-alkalinity-acid-weak alkalinity" and two-stage of hydrocarbon filling. The diagenetic sequences are summarized as "early compaction/early pyrite/gypsum/calcite/dolomite cementation→feldspar dissolution/the first stage of quartz overgrowth → early hydrocarbon filling→quartz dissolution/anhydrite/Fe-carbonate cementation→Fe-carbonate dissolution/feldspar dissolution/ the second stage of quartz overgrowth→later hydrocarbon filling→later pyrite cementation. In the same diagenetic context, the diagenetic evolution processes that occurred in different sub/micro-facies during progressive burial have resulted in heterogeneous reservoir properties and oiliness. The braided channel reservoirs in fan delta plain are poorly sorted with high matrix contents. The physical properties decrease continually due to the principally strong compaction and weak dissolution. The present properties of braided channel reservoirs are extremely poor, which is evidenced by few oil layers developed in relatively shallow strata while dry layers entirely in deep. The reservoirs both in the underwater distributary channels and mouth bars are well sorted and have a strong ability to resist compaction. Abundant pores are developed in medium-deep strata because of modifications by two-stage of acidic dissolution and hydrocarbon filling. The present properties are relatively well both in the underwater distributary channels and mouth bars and plenty of oil layers are developed in different burial depth. The present reservoir properties both in interdistributary channel and pre-fan delta are poor caused by extensively cementation. Small amounts of oil layers, oil-water layers and oil-bearing layers are developed in relatively shallow strata while dry layers totally in deep.展开更多
The diagenetic environment, diagenetic responses, diagenetic transformation model and formation mechanisms of high-quality reservoirs(beach-bar sandstones of the Paleogene fourth member) in the Dongying depression wer...The diagenetic environment, diagenetic responses, diagenetic transformation model and formation mechanisms of high-quality reservoirs(beach-bar sandstones of the Paleogene fourth member) in the Dongying depression were studied through the analysis of fluid inclusions, thin section and burial evolution history. The diagenetic fluids of the beach-bar sandstone reservoirs evolved from early high salinity and weak alkalinity to low salinity and strong acidity, late high salinity and strong alkalinity and late low salinity and acidity, which were accompanied by two stages of oil and gas filling. The fluids at the margins of the sandbodies were continuously highly saline and strongly alkaline. The western(eastern) reservoirs experienced early open(closed), middle open, and late closed diagenetic environments during their burial history. The flow pattern was characterized by upwelling during the majority of the diagenesis(in the east, a non-circulating pattern transitioned into an upwelling current). Due to the evolution of the diagenetic fluids, the diagenetic sequence of the beach-bar reservoirs was as follows: early weak carbonate cementation; feldspar and carbonate cement dissolution and authigenic quartz cementation; late carbonate and anhydrite cementation, authigenic feldspar cementation, and late quartz dissolution; and late carbonate cementation, feldspar dissolution, and authigenic quartz cementation. The diagenetic strength during these stages varied or was absent altogether in different parts of the reservoirs. Due to the closeness of the diagenetic environment and the flow pattern of the diagenetic fluids, the diagenetic products are variably distributed in the sandstones interbedded with mudstones and in the fault blocks. The evolution of multiple alternating alkaline and acidic diagenetic environments controlled the distribution patterns of the reservoir diagenesis and reservoir space, and the reservoir quality index, RQI, increased gradually from the margins to the centers of the sandstones. The closeness of the diagenetic environment and the flow patterns of the diagenetic fluids controlled the differences in the reservoir properties among the fault blocks. With increasing distance from the oil-source faults, the RQI values in the west gradually decreased and in the east initially increased and then decreased.展开更多
Gas-bearing deposits in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin consist of shoreface sandstones of the highstand systems tract(HST) and transgressive systems tract(TST), an...Gas-bearing deposits in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin consist of shoreface sandstones of the highstand systems tract(HST) and transgressive systems tract(TST), and deltaic sandstones of the lowstand systems tract(LST) and falling stage systems tract(FSST).Detailed petrographic observations suggest that the diagenetic features and related evolution of these deposits cannot be simply characterized and demonstrated in the depth domain.However, the occurrence of diagenetic minerals systematically depends on the studied interval within the HST, TST, LST, and FSST; therefore, diagenesis in this region can be better constrained when studied in the context of the depositional environments and sequence stratigraphic framework.The eogenetic processes in such settings include:(1) microcrystalline siderite precipitated as concretions in almost all environments and systems tracts, which inhibited further mechanical compaction;(2) grain dissolution and kaolinitization occurred in shoreface HST sandstones and deltaic LST and FSST sandstones;(3) glaucony was locally observed, which did not clearly reflect the controls of facies or sequence stratigraphy; and(4) cementation by pyrite aggregates occurred in the shoreface HST sandstones and deltaic LST sandstones.The mesogenetic diagenesis includes:(1) partial conversion of kaolinite into dickite in deltaic LST sandstones, and minor chlorite cementation in deltaic FSST sandstones;(2) transformation of kaolinite into illite and quartz cementation in deltaic LST and FSST sandstones;(3) frequent precipitation of ankerite and ferroan calcite in shoreface TST sandstones and early HST sandstones, forming baffles and barriers for fluid flow, with common calcite in shoreface HST sandstones as a late diagenetic cement; and(4) formation of dawsonite in the deltaic LST and FSST sandstones, which is interpreted to be a product of the invasion of a CO2-rich fluid, and acts as a good indicator of CO2-bearing reservoirs.This study has thus constructed a reliable conceptual model to describe the spatial and temporal distribution of diagenetic alterations.The results may provide an entirely new conceptual framework and methodology for successful gas exploration in the continental margins of offshore China, thus allowing us to predict and unravel the distribution and quality evolution of clastic reservoirs at a more detailed and reliable scale.展开更多
Based on the petrology,isotope geochemistry and fluid inclusions analysis,we established the evolutionary mode of the diagenetic fluid of dawsonite-bearing sandstone in the Jiyang Depression.Dawsonite-bearing sandston...Based on the petrology,isotope geochemistry and fluid inclusions analysis,we established the evolutionary mode of the diagenetic fluid of dawsonite-bearing sandstone in the Jiyang Depression.Dawsonite-bearing sandstone is characterized by double injection of CO_(2)and oil-gas in the Jiyang Depression that have experienced a relatively complex diagenetic fluid evolution process.The diagenetic sequence of secondary minerals involves secondary enlargement of quartz,kaolinite,first-stage calcite,dawsonite,second-stage calcite,ferrocalcite,dolomite and ankerite.Hydrocarbon charging in the dawsonite-bearing sandstone occurred at around 2.6–0 Myr.The CO_(2)charging event occurred during Dongying tectonism,forming the Pingfangwang CO_(2)gas reservoir,which provided an abundant carbon source for dawsonite precipitation.Carbon and oxygen isotopic compositions of dawsonite demonstrate that CO_(2)forming the dawsonite was of an inorganic origin derived from the mantle,and that water mediating the proc-ess during dawsonite precipitation was sequestered brine with a fluid temperature of 82℃.The evolutionary sequence of the diagenetic fluid in the dawsonite-bearing sandstone was:alkaline syngenetic fluids,weak alkaline fluids during organic acid forma-tion,acidic fluids in the early stage of CO_(2)injection,alkaline fluids in the late stage of CO_(2)injection,and weak alkaline fluids during oil and gas charging.The mode indicates an increase in-HCO_(3)because of the CO_(2)injection,and the loss of Ca^(2+)and Mg^(2+)due to the precipitation of carbonate minerals.Therefore,the evolutionary mode of diagenetic fluids is in good agreement with high HCO_(3)^(-),low Ca^(2+)and low Mg^(2+)composition of the present formation water in the dawsonite-bearing sandstone.展开更多
Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent year...Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.展开更多
Identification of the S genotype of Malus plants will greatly promote the discovery of new genes,the cultivation and production of apple,the breeding of new varieties,and the origin and evolution of self-incompatibili...Identification of the S genotype of Malus plants will greatly promote the discovery of new genes,the cultivation and production of apple,the breeding of new varieties,and the origin and evolution of self-incompatibility in Malus plants.In this experiment,88 Malus germplasm resources,such as Aihuahong,Xishuhaitang,and Reguanzi,were used as materials.Seven gene-specific primer combinations were used in the genotype identification.PCR amplification using leaf DNA produced a single S-RNase gene fragment in all materials.The results revealed that 70 of the identified materials obtained a complete S-RNase genotype,while only one S-RNase gene was found in 18 of them.Through homology comparison and analysis,13 S-RNase genotypes were obtained:S_(1)S_(2)(Aihuahong,etc.),S_(1)S_(28)(Xixian Haitang,etc.),S_(1)S_(51)(Hebei Pingdinghaitang),S_(1)S_(3)(Xiangyangcun Daguo,etc.),S_(2)S_(3)(Zhaiyehaitang,etc.),S_(3)S_(51)(Xishan 1),S_(3)S_(28)(Huangselihaerde,etc.),S_(2)S_(28)(Honghaitang,etc.),S_(4)S_(28)(Bo 11),S_(7)S_(28)(Jiuquan Shaguo),S_(10)S_e(Dongchengguan 13),S_(10)S_(21)(Dongxiangjiao)and S_(3)S_(51)(Xiongyue Haitang).Simultaneously,the frequency of the S gene in the tested materials was analyzed.The findings revealed that different S genes had varying frequencies in Malus resources,as well as varying frequencies between intraspecific and interspecific.S_(3) had the highest frequency of 68.18%,followed by S_(1)(42.04%).In addition,the phylogenetic tree and origin evolution analysis revealed that the S gene differentiation was completed prior to the formation of various apple species,that cultivated species also evolved new S genes,and that the S_(50) gene is the oldest S allele in Malus plants.The S_(1),S_(29),and S_(33) genes in apple-cultivated species,on the other hand,may have originated in M.sieversii,M.hupehensis,and M.kansuensis,respectively.In addition to M.sieversii,M.kansuensis and M.sikkimensis may have also played a role in the origin and evolution of some Chinese apples.展开更多
By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the im...By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the improvement in synchronization control between two-stage light gas gun and the transient Raman spectra acquisition,as well as the sample preparation,the Raman peak of the N-O mode of TATB was firstly observed under shock pressure up to 13.6 GPa,noticeably higher than the upper limit of 8.5 GPa reported in available literatures.By taking into account of the continuous shift of the main peak and other observed Raman peaks,we did not distinguish any structural transition or any new species.Moreover,both the present Raman spectra and the time-resolved radiation of TATB during shock loading showed that TATB exhibits higher chemical stability than previous declaration.To reveal the detailed structural response and evolution of TATB under compression,the density functional theoretical calculations were conducted,and it was found that the pressure make N-O bond lengths shorter,nitro bond angles larger,and intermolecular and intra-molecular hydrogen bond interactions enhanced.The observed red shift of Raman peak was ascribed to the abnormal enhancement of H-bound effect on the scissor vibration mode of the nitro group.展开更多
The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide incl...The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide inclusions.Scanning Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes this.However,the density of state calculations through density functional theory using hybrid HSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox reactions.Subsequent determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with HER being found to be a factor of 23x more efficient at the interface than on metallic Mg.The results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.展开更多
Ef fective and robust catalyst is the core of water splitting to produce hydrogen.Here, we report an anionic etching method to tailor the sulfur vacancy(VS) of NiS_(2) to further enhance the electrocatalytic performan...Ef fective and robust catalyst is the core of water splitting to produce hydrogen.Here, we report an anionic etching method to tailor the sulfur vacancy(VS) of NiS_(2) to further enhance the electrocatalytic performance for hydrogen evolution reaction(HER). With the VS concentration change from 2.4% to 8.5%, the H* adsorption strength on S sites changed and NiS_(2)-VS 5.9% shows the most optimized H* adsorption for HER with an ultralow onset potential(68 m V) and has long-term stability for 100 h in 1 M KOH media. In situ attenuated-total-reflection Fourier transform infrared spectroscopy(ATR-FTIRS) measurements are usually used to monitor the adsorption of intermediates. The S-H* peak of the Ni S_(2)-VS 5.9% appears at a very low voltage, which is favorable for the HER in alkaline media. Density functional theory calculations also demonstrate the Ni S_(2)-VS 5.9% has the optimal |ΔG^(H*)| of 0.17 e V. This work offers a simple and promising pathway to enhance catalytic activity via precise vacancies strategy.展开更多
The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain ...The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain trade from 1990 to 2020, focusing on network topology, centrality ranking, and community structure. There are three major findings. First, the global major grain trade network has expanded in scale, with a growing emphasis on diversification and balance. During the study period, the United States, Canada, China, and Brazil were the core nodes of the network. Grain-exporting countries were mainly situated in Asia, the Americas, and Europe, and importing countries in Asia, Africa, and Europe. Second, a significant increase in the number of high centrality countries with high export capacity occurred, benefiting from natural advantages such as fertile land and favorable climates. Third, the main global grain trade network is divided into four communities, with the Americas-Europe community being the largest and most widespread. The formation of the community pattern was influenced by geographic proximity, driven by the core exporting countries. Therefore, the world needs to enhance the existing trade model, promote the multi-polarization of the grain trade network, and establish a global vision for the future community. Countries and regions should participate actively in global grain trade security governance and institutional reform, expand trade links with other countries, and optimize import and export policies to reduce trade risks.展开更多
A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C3N4)have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high lumines...A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C3N4)have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high luminescent quantum efficiency.What is more attractive is that the luminescent properties such as wavelength and intensity can be regulated by controlling the structure at the molecular level.Hence,it is time to summarize the related research on CN structural evolution and make a prospect on future developments.In this review,we first summarize the research history and multiple structural evolution of CN.Then,the progress of improving the luminescence performance of CN through structural evolution was discussed.Significantly,the relationship between CN structure evolution and energy conversion in the forms of photoluminescence,chemiluminescence,and electrochemiluminescence was reviewed.Finally,key challenges and opportunities such as nanoscale dispersion strategy,luminous efficiency improving methods,standardization evaluation,and macroscopic preparation of CN are highlighted.展开更多
Tackling the problem of poor conductivity and catalytic stability of pristine metal-organic frameworks(MOFs) is crucial to improve their oxygen evolution reaction(OER) performance.Herein,we introduce a novel strategy ...Tackling the problem of poor conductivity and catalytic stability of pristine metal-organic frameworks(MOFs) is crucial to improve their oxygen evolution reaction(OER) performance.Herein,we introduce a novel strategy of dysprosium(Dy) doping,using the unique 4f orbitals of this rare earth element to enhance electrocatalytic activity of MOFs.Our method involves constructing Dy-doped Ni-MOF(Dy@Ni-MOF) nanoneedles on carbon cloth via a Dy-induced valence electronic perturbation approach.Experiments and density functional theory(DFT) calculations reveal that Dy doping can effectively modify the electronic structure of the Ni active centers and foster a strong electronic interaction between Ni and Dy.The resulting benefits include a reduced work function and a closer proximity of the d-band center to the Fermi level,which is conducive to improving electrical conductivity and promoting the adsorption of oxygen-containing intermediates.Furthermore,the Dy@Ni-MOF achieves superhydrophilicity,ensuring effective electrolyte contact and thus accelerating reaction kinetics,Ex-situ and in-situ analysis results manifest Dy_(2)O_(3)/NiOOH as the actual active species.Therefore,Dy@Ni-MOF shows impressive OER performance,significantly surpassing Ni-MOF.Besides,the overall water splitting device with Dy@NiMOF as an anode delivers a low cell voltage of 1.51 V at 10 mA cm^(-2) and demonstrates long-term stability for 100 h,positioning it as a promising substitute for precious metal catalysts.展开更多
With the rapid urbanization process,the space of traditional villages in China is undergoing significant changes.Studying the spatial evolution of traditional villages is significant in promoting rural spatial transfo...With the rapid urbanization process,the space of traditional villages in China is undergoing significant changes.Studying the spatial evolution of traditional villages is significant in promoting rural spatial transformation and realizing rural revitalization and sustainable rural development.Based on the traceability analysis of spatial production theory,this paper constructed an analytical framework for the spatial production evolution of traditional villages,analyzed the spatial evolution process and characteristics of traditional villages by using buffer analysis,spatial syntax,and other research methods,and revealed the characteristics of the spatial production evolution of traditional villages and the driving mechanism.The results show that:(1)The village spatial formation and development follow the village life cycle theory and usually develop from embryonic villages to diversified and integrated villages;(2)The evolution of village spatial production is characterized by the diversity of material space,the sublimation of daily life space,and the integration of social system space and generalization of emotional space;(3)The evolution of village spatial production from backward and poor village to ecologically well-off village is influenced by a combination of factors;(4)The village has formed a spatial structure of"people-land-scape-culture-industry",realized comprehensive reconstruction and spatial reproduction.The study results reflect the spatial evolution characteristics of traditional villages in mountainous areas in a more comprehensive way,which helps to promote the protection and development of traditional villages in mountainous areas and,to a certain extent,provides a reference for the development of rural revitalization.展开更多
Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy...Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.展开更多
The incorporation of partial A-site substitution in perovskite oxides represents a promising strategy for precisely controlling the electronic configuration and enhancing its intrinsic catalytic activity.Conventional ...The incorporation of partial A-site substitution in perovskite oxides represents a promising strategy for precisely controlling the electronic configuration and enhancing its intrinsic catalytic activity.Conventional methods for A-site substitution typically involve prolonged high-temperature processes.While these processes promote the development of unique nanostructures with highly exposed active sites,they often result in the uncontrolled configuration of introduced elements.Herein,we present a novel approach for synthesizing two-dimensional(2D)porous GdFeO_(3) perovskite with A-site strontium(Sr)substitution utilizing microwave shock method.This technique enables precise control of the Sr content and simultaneous construction of 2D porous structures in one step,capitalizing on the advantages of rapid heating and cooling(temperature~1100 K,rate~70 K s^(-1)).The active sites of this oxygen-rich defect structure can be clearly revealed through the simulation of the electronic configuration and the comprehensive analysis of the crystal structure.For electrocatalytic oxygen evolution reaction application,the synthesized 2D porous Gd_(0.8)Sr_(0.2)FeO_(3) electrocatalyst exhibits an exceptional overpotential of 294 mV at a current density of 10 mA cm^(-2)and a small Tafel slope of 55.85 mV dec^(-1)in alkaline electrolytes.This study offers a fresh perspective on designing crystal configurations and the construction of nanostructures in perovskite.展开更多
Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will ben...Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts.Herein,Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mAcm−2.Additionally,it had an overpotential of 260 mV(glassy carbon)or 215 mV(nickel foam),which was 78 mV lower than that of IrO_(2)(338 mV).In situ,Raman spectroscopy revealed the transformation process of CoOOH.Calculations using the density functional theory showed that during OER,doped Mo increased the spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process,which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials.Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.展开更多
The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clu...The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.42172153,41802172)Sinopec Key Laboratory Project(Grant No.KL21042)Shengli Oilfield Company Project(Grant No.YKS2101)。
文摘The origin of dolomite in Shahejie Formation shale of Jiyang Depression in eastern China were studied by means of petrologic identification, compositional analysis by X-ray diffraction, stable carbon and oxygen isotopic composition, and trace element and rare earth element analyses. The results show that the development of dolomite is limited in the lacustrine organic rich shale of Shahejie Formation in the study area. Three kinds of dolomite minerals can be identified: primary dolomite(D1), penecontemporaneous dolomite(D2), and ankerite(Ak). D1 has the structure of primary spherical dolomite, high magnesium and high calcium, with order degree of 0.3-0.5, and is characterized by the intracrystalline corrosion and coexistence of secondary enlargement along the outer edge. D2 has the characteristics of secondary enlargement, order degree of 0.5-0.7, high magnesium, high calcium and containing a little iron and manganese elements. Ak is characterized by high order degree of 0.7-0.9, rhombic crystal, high magnesium, high calcium and high iron. The micritic calcite belongs to primary origin on the basis of the carbon and oxygen isotopic compositions and the fractionation characteristics of rare earth elements. According to the oxygen isotopic fractionation equation between paragenetic dolomite and calcite, it is calculated that the formation temperature of dolomite in the shale is between 36.76-45.83 ℃, belonging to lacustrine low-temperature dolomite. Based on the maturation and growth mechanism of primary and penecontemporaneous dolomite crystals, a dolomite diagenetic sequence and the dolomitization process are proposed, which is corresponding to the diagenetic environment of Shahejie Formation shale in the study area.
基金Major Projects of National Science and Technology "Large Oil and Gas Fields and CBM Development" (Grant No.2016ZX05027-02–007)the National Natural Science Fund(Grant No.42072119)Open Foundation of Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education(China University of Geosciences)(Grant No.TPR-2021–08)。
文摘It was showed that understanding of the diagenetic modifications and its associated products in the deeply to ultra-deeply buried tight sandstone reservoirs(DUDTSR)is great important for reservoir characterization and hydrocarbon prediction.However,the fine characterization of diagenetic evolution via geologic modelling in tight sandstones remains a great challenge as for complexity of lithology,temperature,pressure and formation fluid throughout the entire life cycle of tight sandstone reservoirs.To help get a comprehensive idea of the distribution of diagenetic processes on the formation of DUDTSR in the long geological period,type-I and type-II fine sections of diagenetic stage for clastic reservoirs were creatively proposed and its essence was illustrated using the Paleogene Huagang(EH)Formation in the southern Xihu Sag.Through combination of both quantitative and qualitative methods which began with current formation temperature,vitrinite analysis,illite and I/S mixed layers based on analytical testing of the EH Formation,(1)Paleotemperature(T),vitrinite reflectivity and smectite in mixed layer during burial processes were restored based on numerical analysis,(2)The accurate division of diagenetic evolution was identified from coarse to fine process using new model,(3)And finally the geological significance of fine division of the conventional diagenetic stage was illustrated for low-porosity and tight sandstone reservoirs.
基金Supported by the China National Science and Technology Major Project (2016ZX05006-006)
文摘The reservoir properties, diagenetic features and evolution of the Paleogene Shahejie Formation(Es) in the Nanpu sag, Bohai Bay Basin were analyzed based on mineralogical and petrological data, and the main controlling factors and formation mechanisms of medium to deep high-quality reservoir were revealed by multiple regression analysis. The results show that the sedimentary microfacies, rigid grains content, and dissolution process are the key factors controlling the formation of high-quality clastic reservoir in middle to deep depth in the Nanpu sag. The formation mechanisms of middle to deep sandstones of the Es in different structural belts differ widely in formation mechanism. The Es1(uppermost member of Es) sandstone reservoirs in the Nanpu No.3 structural belt is low porosity, moderate to high permeability reservoir in the mesodiagenesis A2 stage on the whole, and the formation of high-quality reservoirs is mainly attributed to strong compaction resistance ability primarily, and dissolution process secondarily. The Es3(third member of Es) sandstones in Gaoshangpu structural belt is classified as tight sandstones in the mesodiagenesis A1 stage, in which the development of favorable reservoirs is primarily controlled by dissolution. This study provides references for reservoir evaluation of deep clastic reservoirs and exploration deployment in the Bohai Bay rift basin. As there are high-quality reservoirs, it is believed that the deep clastic reservoirs in the eastern of China, such as Bohai Bay Basin still have significant exploration potential.
基金Project(41102058)supported by the National Natural Science Foundation of ChinaProject(2011ZX05006-003)supported by National Oil&Gas Major Project of China+1 种基金Project(U1262203)supported by Key Program for National Natural Science Foundation of ChinaProject(LW140101A)for Excellent Doctoral Dissertation supported by China University of Petroleum,China
文摘Petrographic analysis combined with various techniques, such as thin section identification, fluid inclusions, isotopic data, petro-physical property testing and oil testing results, was used to study diagenetic evolution and its effect on reservoir-quality of fan delta reservoirs of Es4s in the Bonan sag. The diagenesis is principally characterized by strong compaction, undercompaction, multi-phase of dissolution and cementation. Compaction played a more important role than cementation in destroying the primary porosity of the sandstones. The reservoirs have experienced complicated diagenetic environment evolution of "weak alkalineacid-alkalinity-acid-weak alkalinity" and two-stage of hydrocarbon filling. The diagenetic sequences are summarized as "early compaction/early pyrite/gypsum/calcite/dolomite cementation→feldspar dissolution/the first stage of quartz overgrowth → early hydrocarbon filling→quartz dissolution/anhydrite/Fe-carbonate cementation→Fe-carbonate dissolution/feldspar dissolution/ the second stage of quartz overgrowth→later hydrocarbon filling→later pyrite cementation. In the same diagenetic context, the diagenetic evolution processes that occurred in different sub/micro-facies during progressive burial have resulted in heterogeneous reservoir properties and oiliness. The braided channel reservoirs in fan delta plain are poorly sorted with high matrix contents. The physical properties decrease continually due to the principally strong compaction and weak dissolution. The present properties of braided channel reservoirs are extremely poor, which is evidenced by few oil layers developed in relatively shallow strata while dry layers entirely in deep. The reservoirs both in the underwater distributary channels and mouth bars are well sorted and have a strong ability to resist compaction. Abundant pores are developed in medium-deep strata because of modifications by two-stage of acidic dissolution and hydrocarbon filling. The present properties are relatively well both in the underwater distributary channels and mouth bars and plenty of oil layers are developed in different burial depth. The present reservoir properties both in interdistributary channel and pre-fan delta are poor caused by extensively cementation. Small amounts of oil layers, oil-water layers and oil-bearing layers are developed in relatively shallow strata while dry layers totally in deep.
基金jointly funded by the National Nature Science Foundation of China(grants No.41402095 and U1262203)the Fundamental Research Funds for the Central Universities(grants No.16CX02027A and 15CX08001A)the Scientific and Technological Innovation Project Financially Supported by the Qingdao National Laboratory for Marine Science and Technology(grant No.2015ASKJ01)
文摘The diagenetic environment, diagenetic responses, diagenetic transformation model and formation mechanisms of high-quality reservoirs(beach-bar sandstones of the Paleogene fourth member) in the Dongying depression were studied through the analysis of fluid inclusions, thin section and burial evolution history. The diagenetic fluids of the beach-bar sandstone reservoirs evolved from early high salinity and weak alkalinity to low salinity and strong acidity, late high salinity and strong alkalinity and late low salinity and acidity, which were accompanied by two stages of oil and gas filling. The fluids at the margins of the sandbodies were continuously highly saline and strongly alkaline. The western(eastern) reservoirs experienced early open(closed), middle open, and late closed diagenetic environments during their burial history. The flow pattern was characterized by upwelling during the majority of the diagenesis(in the east, a non-circulating pattern transitioned into an upwelling current). Due to the evolution of the diagenetic fluids, the diagenetic sequence of the beach-bar reservoirs was as follows: early weak carbonate cementation; feldspar and carbonate cement dissolution and authigenic quartz cementation; late carbonate and anhydrite cementation, authigenic feldspar cementation, and late quartz dissolution; and late carbonate cementation, feldspar dissolution, and authigenic quartz cementation. The diagenetic strength during these stages varied or was absent altogether in different parts of the reservoirs. Due to the closeness of the diagenetic environment and the flow pattern of the diagenetic fluids, the diagenetic products are variably distributed in the sandstones interbedded with mudstones and in the fault blocks. The evolution of multiple alternating alkaline and acidic diagenetic environments controlled the distribution patterns of the reservoir diagenesis and reservoir space, and the reservoir quality index, RQI, increased gradually from the margins to the centers of the sandstones. The closeness of the diagenetic environment and the flow patterns of the diagenetic fluids controlled the differences in the reservoir properties among the fault blocks. With increasing distance from the oil-source faults, the RQI values in the west gradually decreased and in the east initially increased and then decreased.
基金Financial support was provided by the National Science and Technology Major Project of China (No.2011ZX05023-002-003)
文摘Gas-bearing deposits in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin consist of shoreface sandstones of the highstand systems tract(HST) and transgressive systems tract(TST), and deltaic sandstones of the lowstand systems tract(LST) and falling stage systems tract(FSST).Detailed petrographic observations suggest that the diagenetic features and related evolution of these deposits cannot be simply characterized and demonstrated in the depth domain.However, the occurrence of diagenetic minerals systematically depends on the studied interval within the HST, TST, LST, and FSST; therefore, diagenesis in this region can be better constrained when studied in the context of the depositional environments and sequence stratigraphic framework.The eogenetic processes in such settings include:(1) microcrystalline siderite precipitated as concretions in almost all environments and systems tracts, which inhibited further mechanical compaction;(2) grain dissolution and kaolinitization occurred in shoreface HST sandstones and deltaic LST and FSST sandstones;(3) glaucony was locally observed, which did not clearly reflect the controls of facies or sequence stratigraphy; and(4) cementation by pyrite aggregates occurred in the shoreface HST sandstones and deltaic LST sandstones.The mesogenetic diagenesis includes:(1) partial conversion of kaolinite into dickite in deltaic LST sandstones, and minor chlorite cementation in deltaic FSST sandstones;(2) transformation of kaolinite into illite and quartz cementation in deltaic LST and FSST sandstones;(3) frequent precipitation of ankerite and ferroan calcite in shoreface TST sandstones and early HST sandstones, forming baffles and barriers for fluid flow, with common calcite in shoreface HST sandstones as a late diagenetic cement; and(4) formation of dawsonite in the deltaic LST and FSST sandstones, which is interpreted to be a product of the invasion of a CO2-rich fluid, and acts as a good indicator of CO2-bearing reservoirs.This study has thus constructed a reliable conceptual model to describe the spatial and temporal distribution of diagenetic alterations.The results may provide an entirely new conceptual framework and methodology for successful gas exploration in the continental margins of offshore China, thus allowing us to predict and unravel the distribution and quality evolution of clastic reservoirs at a more detailed and reliable scale.
基金supported by the National Natural Science Foundation of China(Nos.42072130,41872152).
文摘Based on the petrology,isotope geochemistry and fluid inclusions analysis,we established the evolutionary mode of the diagenetic fluid of dawsonite-bearing sandstone in the Jiyang Depression.Dawsonite-bearing sandstone is characterized by double injection of CO_(2)and oil-gas in the Jiyang Depression that have experienced a relatively complex diagenetic fluid evolution process.The diagenetic sequence of secondary minerals involves secondary enlargement of quartz,kaolinite,first-stage calcite,dawsonite,second-stage calcite,ferrocalcite,dolomite and ankerite.Hydrocarbon charging in the dawsonite-bearing sandstone occurred at around 2.6–0 Myr.The CO_(2)charging event occurred during Dongying tectonism,forming the Pingfangwang CO_(2)gas reservoir,which provided an abundant carbon source for dawsonite precipitation.Carbon and oxygen isotopic compositions of dawsonite demonstrate that CO_(2)forming the dawsonite was of an inorganic origin derived from the mantle,and that water mediating the proc-ess during dawsonite precipitation was sequestered brine with a fluid temperature of 82℃.The evolutionary sequence of the diagenetic fluid in the dawsonite-bearing sandstone was:alkaline syngenetic fluids,weak alkaline fluids during organic acid forma-tion,acidic fluids in the early stage of CO_(2)injection,alkaline fluids in the late stage of CO_(2)injection,and weak alkaline fluids during oil and gas charging.The mode indicates an increase in-HCO_(3)because of the CO_(2)injection,and the loss of Ca^(2+)and Mg^(2+)due to the precipitation of carbonate minerals.Therefore,the evolutionary mode of diagenetic fluids is in good agreement with high HCO_(3)^(-),low Ca^(2+)and low Mg^(2+)composition of the present formation water in the dawsonite-bearing sandstone.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51902101 and 21875203)the Natural Science Foundation of Hunan Province(Nos.2021JJ40044 and 2023JJ50287)Natural Science Foundation of Jiangsu Province(No.BK20201381).
文摘Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.
基金financially supported by the Agricultural Science and Technology Innovation Program(CAASASTIP-2021-RIP-02)。
文摘Identification of the S genotype of Malus plants will greatly promote the discovery of new genes,the cultivation and production of apple,the breeding of new varieties,and the origin and evolution of self-incompatibility in Malus plants.In this experiment,88 Malus germplasm resources,such as Aihuahong,Xishuhaitang,and Reguanzi,were used as materials.Seven gene-specific primer combinations were used in the genotype identification.PCR amplification using leaf DNA produced a single S-RNase gene fragment in all materials.The results revealed that 70 of the identified materials obtained a complete S-RNase genotype,while only one S-RNase gene was found in 18 of them.Through homology comparison and analysis,13 S-RNase genotypes were obtained:S_(1)S_(2)(Aihuahong,etc.),S_(1)S_(28)(Xixian Haitang,etc.),S_(1)S_(51)(Hebei Pingdinghaitang),S_(1)S_(3)(Xiangyangcun Daguo,etc.),S_(2)S_(3)(Zhaiyehaitang,etc.),S_(3)S_(51)(Xishan 1),S_(3)S_(28)(Huangselihaerde,etc.),S_(2)S_(28)(Honghaitang,etc.),S_(4)S_(28)(Bo 11),S_(7)S_(28)(Jiuquan Shaguo),S_(10)S_e(Dongchengguan 13),S_(10)S_(21)(Dongxiangjiao)and S_(3)S_(51)(Xiongyue Haitang).Simultaneously,the frequency of the S gene in the tested materials was analyzed.The findings revealed that different S genes had varying frequencies in Malus resources,as well as varying frequencies between intraspecific and interspecific.S_(3) had the highest frequency of 68.18%,followed by S_(1)(42.04%).In addition,the phylogenetic tree and origin evolution analysis revealed that the S gene differentiation was completed prior to the formation of various apple species,that cultivated species also evolved new S genes,and that the S_(50) gene is the oldest S allele in Malus plants.The S_(1),S_(29),and S_(33) genes in apple-cultivated species,on the other hand,may have originated in M.sieversii,M.hupehensis,and M.kansuensis,respectively.In addition to M.sieversii,M.kansuensis and M.sikkimensis may have also played a role in the origin and evolution of some Chinese apples.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072299,11902276)the Natural Science Foundation of Sichuan Province(Grant No.2022NSFSC1802)+1 种基金the Basic Research Project of Southwest Jiaotong University(Grant No.2682023ZTPY009)the National Key Laboratory for Shock Wave and Detonation Physics of China(Grant No.JCKYS2019212007)。
文摘By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the improvement in synchronization control between two-stage light gas gun and the transient Raman spectra acquisition,as well as the sample preparation,the Raman peak of the N-O mode of TATB was firstly observed under shock pressure up to 13.6 GPa,noticeably higher than the upper limit of 8.5 GPa reported in available literatures.By taking into account of the continuous shift of the main peak and other observed Raman peaks,we did not distinguish any structural transition or any new species.Moreover,both the present Raman spectra and the time-resolved radiation of TATB during shock loading showed that TATB exhibits higher chemical stability than previous declaration.To reveal the detailed structural response and evolution of TATB under compression,the density functional theoretical calculations were conducted,and it was found that the pressure make N-O bond lengths shorter,nitro bond angles larger,and intermolecular and intra-molecular hydrogen bond interactions enhanced.The observed red shift of Raman peak was ascribed to the abnormal enhancement of H-bound effect on the scissor vibration mode of the nitro group.
基金Agency for Science,Technology and Research(A*STAR),under the RIE2020 Advanced Manufacturing and Engineering(AME)Programmatic Grant(Grant no.A18B1b0061)。
文摘The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide inclusions.Scanning Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes this.However,the density of state calculations through density functional theory using hybrid HSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox reactions.Subsequent determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with HER being found to be a factor of 23x more efficient at the interface than on metallic Mg.The results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.
基金funded by the National Natural Science Foundation of China (NSFC) (Nos. 22221001, 22201115, 21931001, and 21922105)the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province (2019ZX–04)+3 种基金the 111 Project (B20027)by the Fundamental Research Funds for the Central Universities (lzujbky-2023-eyt03)support Natural Science Foundation of Gansu Providence (22JR5RA540)Gansu Province Youth Science and Technology Talent Promotion Project (GXH202220530-02)。
文摘Ef fective and robust catalyst is the core of water splitting to produce hydrogen.Here, we report an anionic etching method to tailor the sulfur vacancy(VS) of NiS_(2) to further enhance the electrocatalytic performance for hydrogen evolution reaction(HER). With the VS concentration change from 2.4% to 8.5%, the H* adsorption strength on S sites changed and NiS_(2)-VS 5.9% shows the most optimized H* adsorption for HER with an ultralow onset potential(68 m V) and has long-term stability for 100 h in 1 M KOH media. In situ attenuated-total-reflection Fourier transform infrared spectroscopy(ATR-FTIRS) measurements are usually used to monitor the adsorption of intermediates. The S-H* peak of the Ni S_(2)-VS 5.9% appears at a very low voltage, which is favorable for the HER in alkaline media. Density functional theory calculations also demonstrate the Ni S_(2)-VS 5.9% has the optimal |ΔG^(H*)| of 0.17 e V. This work offers a simple and promising pathway to enhance catalytic activity via precise vacancies strategy.
基金funded by the National Natural Science Foundation of China(42271313)the Chinese Academy of Agricultural Sciences Innovation Project(CAAS-ASTIP2021-AII)the Central Public-interest Scientific Institution Basal Research Fund,China(JBYW-AII-2022-06,JBYWAII-2022-40)。
文摘The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain trade from 1990 to 2020, focusing on network topology, centrality ranking, and community structure. There are three major findings. First, the global major grain trade network has expanded in scale, with a growing emphasis on diversification and balance. During the study period, the United States, Canada, China, and Brazil were the core nodes of the network. Grain-exporting countries were mainly situated in Asia, the Americas, and Europe, and importing countries in Asia, Africa, and Europe. Second, a significant increase in the number of high centrality countries with high export capacity occurred, benefiting from natural advantages such as fertile land and favorable climates. Third, the main global grain trade network is divided into four communities, with the Americas-Europe community being the largest and most widespread. The formation of the community pattern was influenced by geographic proximity, driven by the core exporting countries. Therefore, the world needs to enhance the existing trade model, promote the multi-polarization of the grain trade network, and establish a global vision for the future community. Countries and regions should participate actively in global grain trade security governance and institutional reform, expand trade links with other countries, and optimize import and export policies to reduce trade risks.
基金supported by the Natural Science Foundation of Hebei Province(Grant No.E2022209039)Key Research Project of North China University of Science and Technology(Grant No.ZD-YG-202301)Tangshan Talent Funding Project(Grant No.A202202007).
文摘A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C3N4)have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high luminescent quantum efficiency.What is more attractive is that the luminescent properties such as wavelength and intensity can be regulated by controlling the structure at the molecular level.Hence,it is time to summarize the related research on CN structural evolution and make a prospect on future developments.In this review,we first summarize the research history and multiple structural evolution of CN.Then,the progress of improving the luminescence performance of CN through structural evolution was discussed.Significantly,the relationship between CN structure evolution and energy conversion in the forms of photoluminescence,chemiluminescence,and electrochemiluminescence was reviewed.Finally,key challenges and opportunities such as nanoscale dispersion strategy,luminous efficiency improving methods,standardization evaluation,and macroscopic preparation of CN are highlighted.
基金supported by the National Natural Science Foundation of China(52363028,21965005)the Natural Science Foundation of Guangxi Province(2021GXNSFAA076001)the Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20297039)。
文摘Tackling the problem of poor conductivity and catalytic stability of pristine metal-organic frameworks(MOFs) is crucial to improve their oxygen evolution reaction(OER) performance.Herein,we introduce a novel strategy of dysprosium(Dy) doping,using the unique 4f orbitals of this rare earth element to enhance electrocatalytic activity of MOFs.Our method involves constructing Dy-doped Ni-MOF(Dy@Ni-MOF) nanoneedles on carbon cloth via a Dy-induced valence electronic perturbation approach.Experiments and density functional theory(DFT) calculations reveal that Dy doping can effectively modify the electronic structure of the Ni active centers and foster a strong electronic interaction between Ni and Dy.The resulting benefits include a reduced work function and a closer proximity of the d-band center to the Fermi level,which is conducive to improving electrical conductivity and promoting the adsorption of oxygen-containing intermediates.Furthermore,the Dy@Ni-MOF achieves superhydrophilicity,ensuring effective electrolyte contact and thus accelerating reaction kinetics,Ex-situ and in-situ analysis results manifest Dy_(2)O_(3)/NiOOH as the actual active species.Therefore,Dy@Ni-MOF shows impressive OER performance,significantly surpassing Ni-MOF.Besides,the overall water splitting device with Dy@NiMOF as an anode delivers a low cell voltage of 1.51 V at 10 mA cm^(-2) and demonstrates long-term stability for 100 h,positioning it as a promising substitute for precious metal catalysts.
基金supported by the National Natural Science Foundation of China(Grant No.42061035)the Guizhou Provincial Program on Commercialization of Scientific and Technological Achievements([2022]010).
文摘With the rapid urbanization process,the space of traditional villages in China is undergoing significant changes.Studying the spatial evolution of traditional villages is significant in promoting rural spatial transformation and realizing rural revitalization and sustainable rural development.Based on the traceability analysis of spatial production theory,this paper constructed an analytical framework for the spatial production evolution of traditional villages,analyzed the spatial evolution process and characteristics of traditional villages by using buffer analysis,spatial syntax,and other research methods,and revealed the characteristics of the spatial production evolution of traditional villages and the driving mechanism.The results show that:(1)The village spatial formation and development follow the village life cycle theory and usually develop from embryonic villages to diversified and integrated villages;(2)The evolution of village spatial production is characterized by the diversity of material space,the sublimation of daily life space,and the integration of social system space and generalization of emotional space;(3)The evolution of village spatial production from backward and poor village to ecologically well-off village is influenced by a combination of factors;(4)The village has formed a spatial structure of"people-land-scape-culture-industry",realized comprehensive reconstruction and spatial reproduction.The study results reflect the spatial evolution characteristics of traditional villages in mountainous areas in a more comprehensive way,which helps to promote the protection and development of traditional villages in mountainous areas and,to a certain extent,provides a reference for the development of rural revitalization.
基金supported by the National Natural Sci-ence Foundation of China(22272081),Jiangsu Provincial Specially Appointed Professors Foundation.
文摘Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.
基金financial support from the National Natural Science Foundation of China (52203070)the Open Fund of State Key Laboratory of New Textile Materials and Advanced Processing Technologies (FZ2022005)+2 种基金the Open Fund of Hubei Key Laboratory of Biomass Fiber and Ecological Dyeing and Finishing (STRZ202203)the financial support provided by the China Scholarship Council (CSC)Visiting Scholar Programfinancial support from Institute for Sustainability,Energy and Resources,The University of Adelaide,Future Making Fellowship,Australia。
文摘The incorporation of partial A-site substitution in perovskite oxides represents a promising strategy for precisely controlling the electronic configuration and enhancing its intrinsic catalytic activity.Conventional methods for A-site substitution typically involve prolonged high-temperature processes.While these processes promote the development of unique nanostructures with highly exposed active sites,they often result in the uncontrolled configuration of introduced elements.Herein,we present a novel approach for synthesizing two-dimensional(2D)porous GdFeO_(3) perovskite with A-site strontium(Sr)substitution utilizing microwave shock method.This technique enables precise control of the Sr content and simultaneous construction of 2D porous structures in one step,capitalizing on the advantages of rapid heating and cooling(temperature~1100 K,rate~70 K s^(-1)).The active sites of this oxygen-rich defect structure can be clearly revealed through the simulation of the electronic configuration and the comprehensive analysis of the crystal structure.For electrocatalytic oxygen evolution reaction application,the synthesized 2D porous Gd_(0.8)Sr_(0.2)FeO_(3) electrocatalyst exhibits an exceptional overpotential of 294 mV at a current density of 10 mA cm^(-2)and a small Tafel slope of 55.85 mV dec^(-1)in alkaline electrolytes.This study offers a fresh perspective on designing crystal configurations and the construction of nanostructures in perovskite.
基金The National Natural Science Foundation of China(Grant Nos.52072114 and 51922008)the 111 Project(Grant No.D17007),the Henan Center for Outstanding Overseas Scientists(Grant No.GZS2018003)+2 种基金Xinxiang Major Science and Technology Projects(Grant No.21ZD001)Guangdong Innovative and Entrepreneurial Research Team Program(2016ZT06N500)Guangdong Provincial Key Laboratory of Energy Materials for Electric Power(2018B030322001)all provided financial support for this work.
文摘Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts.Herein,Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mAcm−2.Additionally,it had an overpotential of 260 mV(glassy carbon)or 215 mV(nickel foam),which was 78 mV lower than that of IrO_(2)(338 mV).In situ,Raman spectroscopy revealed the transformation process of CoOOH.Calculations using the density functional theory showed that during OER,doped Mo increased the spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process,which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials.Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.
基金supported by the National Natural Science Foundation of China(22205209,52202373 and U21A200972)China Postdoctoral Science Foundation(2022M722867)Key Research Project of Higher Education Institutions in Henan Province(23A530001)。
文摘The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.
