The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-b...The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.展开更多
The paper proposes a biomass cross-upgrading process that combines hydrothermal carbonization and pyrolysis to produce high-quality blast furnace injection fuel.The results showed that after upgrading,the volatile con...The paper proposes a biomass cross-upgrading process that combines hydrothermal carbonization and pyrolysis to produce high-quality blast furnace injection fuel.The results showed that after upgrading,the volatile content of biochar ranged from 16.19%to 45.35%,and the alkali metal content,ash content,and specific surface area were significantly reduced.The optimal route for biochar pro-duction is hydrothermal carbonization-pyrolysis(P-HC),resulting in biochar with a higher calorific value,C=C structure,and increased graphitization degree.The apparent activation energy(E)of the sample ranges from 199.1 to 324.8 kJ/mol,with P-HC having an E of 277.8 kJ/mol,lower than that of raw biomass,primary biochar,and anthracite.This makes P-HC more suitable for blast furnace injection fuel.Additionally,the paper proposes a path for P-HC injection in blast furnaces and calculates potential environmental benefits.P-HC of-fers the highest potential for carbon emission reduction,capable of reducing emissions by 96.04 kg/t when replacing 40wt%coal injec-tion.展开更多
The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledim...The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH4Cl and KClO3 were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO3 was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+and V3+/V2+reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm−2 for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7%from 55.2%for the pristine cell at 260 mA cm−2.Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.展开更多
With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy stor...With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy storage device.However,the limitations suffered by AZIBs,including volume expansion and active materials dissolution of the cathode,electrochemical corrosion,irreversible side reactions,zinc dendrites of the anode,have seriously decelerated the civilianization process of AZIBs.Currently,polymers have tremendous superiority for application in AZIBs attributed to their exceptional chemical stability,tunable structure,high energy density and outstanding mechanical properties.Considering the expanding applications of AZIBs and the superiority of polymers,this comprehensive paper meticulously reviews the benefits of utilizing polymeric applied to cathodes and anodes,respectively.To begin with,with adjustable structure as an entry point,the correlation between polymer structure and the function of energy storage as well as optimization is deeply investigated in respect to the mechanism.Then,depending on the diversity of properties and structures,the development of polymers in AZIBs is summarized,including conductive polymers,redox polymers as well as carbon composite polymers for cathode and polyvinylidene fluoride-,carbonyl-,amino-,nitrile-based polymers for anode,and a comprehensive evaluation of the shortcomings of these strategies is provided.Finally,an outlook highlights some of the challenges posed by the application of polymers and offers insights into the potential future direction of polymers in AZIBs.It is designed to provide a thorough reference for researchers and developers working on polymer for AZIBs.展开更多
Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and storage.By utilizing semiconductor photoelectrodes,PEC devices can harness solar energy...Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and storage.By utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added chemicals.However,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical implementation.Recently,significant research has been conducted to improve the overall conversion efficiency of PEC devices.One particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy conversion.This review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) reduction.The main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/hydroxides.Meanwhile,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based cocatalysts.In addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with cocatalysts.Finally,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.展开更多
Biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited catalytic performance.Herein,we proposed a computation-aided surface charge engineering strategy...Biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited catalytic performance.Herein,we proposed a computation-aided surface charge engineering strategy to improve the catalytic performance of haloalkane dehalogenase DhaA in OSs based on the energetic analysis of substrate binding to the DhaA surface.Several variants with enhanced OS resistance were obtained by replacing negative charged residues on the surface with positive charged residue(Arg).Particularly,a four-substitution variant E16R/E93R/E121R/E257R exhibited the best catalytic performance(five-fold improvement in OS resistance and seven-fold half-life increase in 40%(vol)dimethylsulfoxide).As a result,the overall catalytic performance of the variant could be at least 26 times higher than the wild-type DhaA.Fluorescence spectroscopy and molecular dynamics simulation studies revealed that the residue substitution mainly enhanced OS resistance from four aspects:(a)improved the overall structural stability,(b)increased the hydrophobicity of the local microenvironment around the catalytic triad,(c)enriched the hydrophobic substrate around the enzyme molecule,and(d)lowered the contact frequency between OS molecules and the catalytic triad.Our findings validate that computationaided surface charge engineering is an effective and ingenious rational strategy for tailoring enzyme performance in OSs.展开更多
Energy supply dominated by fossil energy has been and remains the main cause of carbon dioxide emissions,the major greenhouse gas leading to the current grave climate change challenges.Many technical pathways have bee...Energy supply dominated by fossil energy has been and remains the main cause of carbon dioxide emissions,the major greenhouse gas leading to the current grave climate change challenges.Many technical pathways have been proposed to address the challenges.Carbon capture and utilization(CCU) represents one of the approaches and thermochemical CO_(2) splitting driven by thermal energy is a subset of the CCU,which converts the captured CO_(2) into CO and makes it possible to achieve closed-loop carbon recirculation.Redox-active catalysts are among the most critical components of the thermochemical splitting cycles and perovskites are regarded as the most promising catalysts.Here we review the latest advancements in thermochemical cycles based on perovskites,covering thermodynamic principles,material modifications,reaction kinetics,oxygen pressure control,circular strategies,and demonstrations to provide a comprehensive overview of the topical area.Thermochemical cycles based on such materials require the consideration of trade-off between cost and efficiency,which is related to actual material used,operation mode,oxygen removal,and heat recovery.Lots of efforts have been made towards improving reaction rates,conversion efficiency and cycling stability,materials related research has been lacking-a key aspect affecting the performance across all above aspects.Double perovskites and composite perovskites arise recently as a potentially promising addition to material candidates.For such materials,more effective oxygen removal would be needed to enhance the overall efficiency,for which thermochemical or electrochemical oxygen pumps could contribute to efficient oxygen removal as well as serve as means for inert gas regeneration.The integration of thermochemical CO_(2) splitting process with downstream fuel production and other processes could reduce costs and increase efficiency of the technology.This represents one of the directions for the future research.展开更多
The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous me...The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.展开更多
Hydrogen-bonded organic frameworks(HOFs)have emerged as a new class of crystalline porous materials,and their application in membrane technology needs to be explored.Herein,for the first time,we demonstrated the utili...Hydrogen-bonded organic frameworks(HOFs)have emerged as a new class of crystalline porous materials,and their application in membrane technology needs to be explored.Herein,for the first time,we demonstrated the utilization of HOF-based mixed-matrix membrane for CO_(2) separation.HOF-21,a unique metallo-hydrogen-bonded organic framework material,was designed and processed into nanofillers via amine modulator,uniformly dispersing with Pebax polymer.Featured with the mix-bonded framework,HOF-21 possessed moderate pore size of 0.35 nm and displayed excellent stability under humid feed gas.The chemical functions of multiple binding sites and continuous hydrogen-bonded network jointly facilitated the mass transport of CO_(2).The resulting HOF-21 mixed-matrix membrane exhibited a permeability above 750 Barrer,a selectivity of~40 for CO_(2)/CH_(4) and~60 for CO_(2)/N_(2),surpassing the 2008 Robeson upper bound.This work enlarges the family of mixed-matrix membranes and lays the foundation for HOF membrane development.展开更多
Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase ...Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase to the 1T phase has been proven to be a significant method to improve the catalytic activity.However,precisely controllable phase engineering of MoSe_(2) has rarely been reported.Herein,by in situ Li ions intercalation in MoSe_(2),a precisely controllable phase evolution from 2H-MoSe_(2) to 1T-MoSe_(2) was realized.More importantly,the definite functional relationship between cut-off voltage and phase structure was first identified for phase engineering through in situ observation and modulation methods.The sulfur host(CNFs/1T-MoSe_(2))presents high charge density,strong polysulfides adsorption,and catalytic kinetics.Moreover,Li-S cells based on it display capacity retention of 875.3mAh g^(-1) after 500 cycles at 1 C and an areal capacity of 8.71mAh cm^(-2) even at a high sulfur loading of 8.47mg cm^(-2).Furthermore,the flexible pouch cell exhibiting decent performance will endow a promising potential in the wearable energy storage field.This study proposes an effective strategy to precisely control the phase structure of MoSe_(2),which may provide the reference to fabricate the highly efficient electrocatalysts for LSBs and other energy systems.展开更多
The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clos...The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.展开更多
The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pre...The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.展开更多
The development of economical,efficient,and robust electrocatalysts toward the hydrogen evolution reaction(HER)is highly imperative for the rapid advancement of renewable H2 energy-associated technologies.Extensive ut...The development of economical,efficient,and robust electrocatalysts toward the hydrogen evolution reaction(HER)is highly imperative for the rapid advancement of renewable H2 energy-associated technologies.Extensive utilization of the heterointerface effect can endow the catalysts with remarkably boosted electrocatalytic performance due to the modified electronic state of active sites.Herein,we demonstrate deliberate crafting of CoP/CoO heterojunction porous nanotubes(abbreviated as CoP/CoO PNTs hereafter)using a self-sacrificial template-engaged strategy.Precise control over the Kirkendall diffusion process of the presynthesized cobalt–aspartic acid complex nanowires is indispensable for the formation of CoP/CoO heterostructures.The topochemical transformation strategy of the reactive templates enables uniform and maximized construction of CoP/CoO heterojunctions throughout all the porous nanotubes.The establishment of CoP/CoO heterojunctions could considerably modify the electronic configuration of the active sites and also improve the electric conductivity,which endows the resultant CoP/CoO PNTs with enhanced intrinsic activity.Simultaneously,the hollow and porous nanotube architectures allow sufficient accessibility of exterior/interior surfaces and molecular permeability,drastically promoting the reaction kinetics.Consequently,when used as HER electrocatalysts,the well-designed CoP/CoO PNTs show Pt-like activity,with an overpotential of only 61 mV at 10mA cm^(−2) and excellent stability in 1.0M KOH medium,exceeding those of the vast majority of the previously reported nonprecious candidates.Density functional theory calculations further substantiate that the construction of CoP/CoO heterojunctions enables optimization of the Gibbs free energies for water adsorption and H adsorption,resulting in boosted HER intrinsic activity.The present study may provide in-depth insights into the fundamental mechanisms of heterojunction-induced electronic regulation,which may pave the way for the rational design of advanced Earth-abundant electrocatalysts in the future.展开更多
Accidents in chemical production usually result in fatal injury,economic loss and negative social impact.Chemical accident reports which record past accident information,contain a large amount of expert knowledge.Howe...Accidents in chemical production usually result in fatal injury,economic loss and negative social impact.Chemical accident reports which record past accident information,contain a large amount of expert knowledge.However,manually finding out the key factors causing accidents needs reading and analyzing of numerous accident reports,which is time-consuming and labor intensive.Herein,in this paper,a semiautomatic method based on natural language process(NLP)technology is developed to construct a knowledge graph of chemical accidents.Firstly,we build a named entity recognition(NER)model using SoftLexicon(simplify the usage of lexicon)+BERT-Transformer-CRF(conditional random field)to automatically extract the accident information and risk factors.The risk factors leading to accident in chemical accident reports are divided into five categories:human,machine,material,management,and environment.Through analysis of the extraction results of different chemical industries and different accident types,corresponding accident prevention suggestions are given.Secondly,based on the definition of classes and hierarchies of information in chemical accident reports,the seven-step method developed at Stanford University is used to construct the ontology-based chemical accident knowledge description model.Finally,the ontology knowledge description model is imported into the graph database Neo4j,and the knowledge graph is constructed to realize the structu red storage of chemical accident knowledge.In the case of information extraction from 290 Chinese chemical accident reports,SoftLexicon+BERT-Transformer-CRF shows the best extraction performance among nine experimental models.Demonstrating that the method developed in the current work can be a promising tool in obtaining the factors causing accidents,which contributes to intelligent accident analysis and auxiliary accident prevention.展开更多
Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the p...Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the pursuit of higher energy density.However,it suffers from serious structural degradation and surface side reactions,in particular,at the voltage above 4.60 V,leading to rapid decay of the battery life.Taking into account the desirable oxygen buffering property and the fast ion mobility characteristic of cerium oxide fluoride,in this work,we prepared Ce&F co-modified LiCoO_(2)by using the precursors of Ce(NO_(3))_(3)·6H_(2)O and NH_(4)F,and evaluated the electrochemical performance under voltages exceeding 4.60 V.The results indicated that the modified samples have multiphase heterostructure of surface CeO_(2-x)and unique Ce-O-F solid solution phase.At 3.0–4.60 V and 25℃,the preferred sample LCO-0.5Ce-0.3F has a high initial discharge specific capacity of 221.9 mA h g^(-1)at 0.1 C,with the retention of 80.3%and 89.6%after 300 cycles at 1 and 5 C,comparing with the pristine LCO(56.4%and 22.6%).And at 3.0–4.65 V,its retention is 64.0%after 300 cycles at 1 C,versus 8.5%of the pristine LCO.Through structural characterizations and DFT calculations,it suggests that Ce^(4+)&F^(-)co-doping suppresses the H3 to H1/3 irreversible phase transition,stabilizes the lattice structure,and reduces the redox activity of the lattice oxygen by modulating the Co 3d–O 2p energy band,consequently improving the electrochemical performance of LiCoO_(2)at high voltages.展开更多
A sol-gel tandem with a solid-phase modification procedure was developed to synthesize Li_(2)TiO_(3)-doped LiCoO_(2) together with phosphate coatings(denoted as LCO-Ti/P),which possesses excellent high-voltage perform...A sol-gel tandem with a solid-phase modification procedure was developed to synthesize Li_(2)TiO_(3)-doped LiCoO_(2) together with phosphate coatings(denoted as LCO-Ti/P),which possesses excellent high-voltage performance in the range of 3.0-4.6 V.The characterizations of X-ray diffraction,high-resolution transmission electron microscopy,and X-ray photoelectron spectroscopy illustrated that the modified sample LCO-Ti/P had the dopant of monoclinic Li_(2)TiO_(3) and amorphous Li3PO4 coating layers.LCO-Ti/P has an initial discharge capacity of 211.6 mAh/g at 0.1 C and a retention of 85.7%after 100 cycles at 1 C and 25±1°C between 3.0 and 4.6 V.Nyquist plots reflect that the charge transfer resistance of LCO-Ti/P after 100 cycles at 1 C is much lower than that of the spent LCO,which benefits Li-ion diffusion.Density functional theory calculations disclose the superior lattice-matching property of major crystal planes for Li_(2)TiO_(3) and LiCoO_(2),the lower energy barriers for Li-ion diffusion in Li_(2)TiO_(3),and the suppressed oxygen release performance resulting from phosphate adsorption.This work provides useful guidance on the rational design of the high-voltage performance of modified LiCoO_(2) materials in terms of lattice-matching properties aside from the phosphate coating to reduce the energy barriers of Li-ion diffusion and enhance cycling stability.展开更多
Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,t...Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.展开更多
Orthorhombic molybdenum trioxide(α-MoO_(3)) electrode material experiences severe capacity fading and poor cycling stability in aqueous electrolytes.We investigated the charge-storage performance of α-MoO_(3) electr...Orthorhombic molybdenum trioxide(α-MoO_(3)) electrode material experiences severe capacity fading and poor cycling stability in aqueous electrolytes.We investigated the charge-storage performance of α-MoO_(3) electrode in aluminium trifluoromethanesulfonate(Al(OTf)_(3))-based salt-in-water electrolyte(SiWE) and water-in-salt electrolyte(WiSE).It was found that α-MoO_(3) electrode exhibits significantly different cycling stabilities in both electrolytes with capacity retentions of 8% using the former and87% using the latter.This is because α-MoO_(3) electrode maintains its crystal structure upon cycling in WiSE,but experiences substantial structural collapses and partial dissolution upon cycling in SiWE.This behaviour was inferred from both operando electrogravimetry and ex situ analyses.Research results suggest that the predominant charge-storage mechanism in a-MoO_(3) electrode using WiSE is the intercalation of protons produced from electrolyte hydrolysis with some contribution from surface pseudocapacitance enabled by Al3+ions.A two-volt full cell fabricated from α-MoO_(3) electrode as anode and copper hexacyanoferrate(CuHCF) electrode as cathode using WiSE delivers volumetric and gravimetric energies of 10.4 Wh/L and 26.5 Wh/kg,respectively,with 78% capacity retention after 2500 cycles.This study provides an insightful understanding of the electrochemical performance of α-MoO_(3) electrode in Al(OTf)_(3)-based electrolytes.展开更多
Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery...Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery damage or fracture is a critical concern.Water-based(aqueous)electrolytes have been receiving attention as an alternative to organic electrolytes.However,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous electrolytes.Therefore,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains challenging.This Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the electrolytes.These aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the electrolytes.In addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.展开更多
Atomically dispersed metal sites(ADMSs)play key roles in electrochemical energy conversion.The covalent organic frameworks(COFs)enable the precise control of the chemical compositions and structures at the molecular l...Atomically dispersed metal sites(ADMSs)play key roles in electrochemical energy conversion.The covalent organic frameworks(COFs)enable the precise control of the chemical compositions and structures at the molecular level,making them ideal substrates for supporting ADMSs.In this review,we systematically summarize the recent progress on the design and synthesis of ADMSs in COFs,including embedding molecular catalysts into COFs,immobilizing ADMSs on heteroatom-containing COFs,and preparing COF-derived carbon materials through pyrolysis.The electrocatalytic performance of the resulting catalysts is presented for various electrochemical reactions,involving oxygen reduction reaction(ORR),carbon dioxide reduction reaction(CO_(2)RR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and nitrogen reduction reaction(NRR).The modulation strategies of AMDSs in COFs for enhanced activity,selectivity,and stability are highlighted,together with a perspective of the current challenges and the future opportunities in this field.展开更多
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant Nos.2018R1A6A1A03024334,2019R1A2C1007637,2021M3I3A1082880,2021R1I1A1A01044174)the Basic Science Research Capacity Enhancement Project through Korea Basic Science Institute (Grant No.2019R1A6C1010024)。
文摘The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.
基金the National Key R&D Program of China(No.2022YFE0208100)the National Natural Science Foundation of China(No.5274316)+1 种基金the Key Research and Development Plan of Anhui Province,China(No.202210700037)the Major Science and Technology Project of Xinjiang Uygur Autonomous Region,China(No.2022A01003).
文摘The paper proposes a biomass cross-upgrading process that combines hydrothermal carbonization and pyrolysis to produce high-quality blast furnace injection fuel.The results showed that after upgrading,the volatile content of biochar ranged from 16.19%to 45.35%,and the alkali metal content,ash content,and specific surface area were significantly reduced.The optimal route for biochar pro-duction is hydrothermal carbonization-pyrolysis(P-HC),resulting in biochar with a higher calorific value,C=C structure,and increased graphitization degree.The apparent activation energy(E)of the sample ranges from 199.1 to 324.8 kJ/mol,with P-HC having an E of 277.8 kJ/mol,lower than that of raw biomass,primary biochar,and anthracite.This makes P-HC more suitable for blast furnace injection fuel.Additionally,the paper proposes a path for P-HC injection in blast furnaces and calculates potential environmental benefits.P-HC of-fers the highest potential for carbon emission reduction,capable of reducing emissions by 96.04 kg/t when replacing 40wt%coal injec-tion.
基金supported by the National Natural Science Foundation of China(No.51872090)Natural Science Foundation of Hebei Province(No.E2019209433,E2022209158)Colleges and Universities in Hebei Province Science and Technology Research Project(No.JZX2024026).
文摘The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH4Cl and KClO3 were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO3 was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+and V3+/V2+reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm−2 for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7%from 55.2%for the pristine cell at 260 mA cm−2.Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.
基金financially supported by the National Natural Science Foundation of China(51872090,51772097,22304055)the Hebei Natural Science Fund for Distinguished Young Scholar(E2019209433)+4 种基金the Youth Talent Program of Hebei Provincial Education Department(BJ2018020)the Natural Science Foundation of Hebei Province(E2020209151,E2022209158,B2022209026,D2023209012)the Central Guiding Local Science and Technology Development Fund Project(236Z4409G)the Science and Technology Project of Hebei Education Department(SLRC2019028)the Science and Technology Planning Project of Tangshan City(22130227H)。
文摘With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy storage device.However,the limitations suffered by AZIBs,including volume expansion and active materials dissolution of the cathode,electrochemical corrosion,irreversible side reactions,zinc dendrites of the anode,have seriously decelerated the civilianization process of AZIBs.Currently,polymers have tremendous superiority for application in AZIBs attributed to their exceptional chemical stability,tunable structure,high energy density and outstanding mechanical properties.Considering the expanding applications of AZIBs and the superiority of polymers,this comprehensive paper meticulously reviews the benefits of utilizing polymeric applied to cathodes and anodes,respectively.To begin with,with adjustable structure as an entry point,the correlation between polymer structure and the function of energy storage as well as optimization is deeply investigated in respect to the mechanism.Then,depending on the diversity of properties and structures,the development of polymers in AZIBs is summarized,including conductive polymers,redox polymers as well as carbon composite polymers for cathode and polyvinylidene fluoride-,carbonyl-,amino-,nitrile-based polymers for anode,and a comprehensive evaluation of the shortcomings of these strategies is provided.Finally,an outlook highlights some of the challenges posed by the application of polymers and offers insights into the potential future direction of polymers in AZIBs.It is designed to provide a thorough reference for researchers and developers working on polymer for AZIBs.
基金supported by the National Research Foundation of Korea (NRF)funded by the Korean government (2021R1A4A3027878,2022M3H4A1A01012712)。
文摘Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and storage.By utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added chemicals.However,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical implementation.Recently,significant research has been conducted to improve the overall conversion efficiency of PEC devices.One particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy conversion.This review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) reduction.The main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/hydroxides.Meanwhile,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based cocatalysts.In addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with cocatalysts.Finally,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.
基金funded by the National Key Research and Development Program of China(2018YFA0900702).
文摘Biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited catalytic performance.Herein,we proposed a computation-aided surface charge engineering strategy to improve the catalytic performance of haloalkane dehalogenase DhaA in OSs based on the energetic analysis of substrate binding to the DhaA surface.Several variants with enhanced OS resistance were obtained by replacing negative charged residues on the surface with positive charged residue(Arg).Particularly,a four-substitution variant E16R/E93R/E121R/E257R exhibited the best catalytic performance(five-fold improvement in OS resistance and seven-fold half-life increase in 40%(vol)dimethylsulfoxide).As a result,the overall catalytic performance of the variant could be at least 26 times higher than the wild-type DhaA.Fluorescence spectroscopy and molecular dynamics simulation studies revealed that the residue substitution mainly enhanced OS resistance from four aspects:(a)improved the overall structural stability,(b)increased the hydrophobicity of the local microenvironment around the catalytic triad,(c)enriched the hydrophobic substrate around the enzyme molecule,and(d)lowered the contact frequency between OS molecules and the catalytic triad.Our findings validate that computationaided surface charge engineering is an effective and ingenious rational strategy for tailoring enzyme performance in OSs.
文摘Energy supply dominated by fossil energy has been and remains the main cause of carbon dioxide emissions,the major greenhouse gas leading to the current grave climate change challenges.Many technical pathways have been proposed to address the challenges.Carbon capture and utilization(CCU) represents one of the approaches and thermochemical CO_(2) splitting driven by thermal energy is a subset of the CCU,which converts the captured CO_(2) into CO and makes it possible to achieve closed-loop carbon recirculation.Redox-active catalysts are among the most critical components of the thermochemical splitting cycles and perovskites are regarded as the most promising catalysts.Here we review the latest advancements in thermochemical cycles based on perovskites,covering thermodynamic principles,material modifications,reaction kinetics,oxygen pressure control,circular strategies,and demonstrations to provide a comprehensive overview of the topical area.Thermochemical cycles based on such materials require the consideration of trade-off between cost and efficiency,which is related to actual material used,operation mode,oxygen removal,and heat recovery.Lots of efforts have been made towards improving reaction rates,conversion efficiency and cycling stability,materials related research has been lacking-a key aspect affecting the performance across all above aspects.Double perovskites and composite perovskites arise recently as a potentially promising addition to material candidates.For such materials,more effective oxygen removal would be needed to enhance the overall efficiency,for which thermochemical or electrochemical oxygen pumps could contribute to efficient oxygen removal as well as serve as means for inert gas regeneration.The integration of thermochemical CO_(2) splitting process with downstream fuel production and other processes could reduce costs and increase efficiency of the technology.This represents one of the directions for the future research.
基金funded by the National Natural Science Foundation of China,China (Nos.52272303 and 52073212)the General Program of Municipal Natural Science Foundation of Tianjin,China (Nos.17JCYBJC22700 and 17JCYBJC17000)the State Scholarship Fund of China Scholarship Council,China (Nos.201709345012 and 201706255009)。
文摘The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.
基金support from National Key Research and Development Program of China(No.2021YFB3802200)National Natural Science Foundation of China(No.U20B2023,22208238,U1732120)+1 种基金the Haihe Laboratory of Sustainable Chemical TransformationsNingbo Natural Science Foundation(No.2021J004).
文摘Hydrogen-bonded organic frameworks(HOFs)have emerged as a new class of crystalline porous materials,and their application in membrane technology needs to be explored.Herein,for the first time,we demonstrated the utilization of HOF-based mixed-matrix membrane for CO_(2) separation.HOF-21,a unique metallo-hydrogen-bonded organic framework material,was designed and processed into nanofillers via amine modulator,uniformly dispersing with Pebax polymer.Featured with the mix-bonded framework,HOF-21 possessed moderate pore size of 0.35 nm and displayed excellent stability under humid feed gas.The chemical functions of multiple binding sites and continuous hydrogen-bonded network jointly facilitated the mass transport of CO_(2).The resulting HOF-21 mixed-matrix membrane exhibited a permeability above 750 Barrer,a selectivity of~40 for CO_(2)/CH_(4) and~60 for CO_(2)/N_(2),surpassing the 2008 Robeson upper bound.This work enlarges the family of mixed-matrix membranes and lays the foundation for HOF membrane development.
基金National Natural Science Foundation of China,Grant/Award Numbers:U2004172,51972287 and 51502269the Foundation for University Key Teachers of Henan Province,Grant/Award Number:2020GGJS009Natural Science Foundation of Henan Province,Grant/Award Number:202300410368。
文摘Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase to the 1T phase has been proven to be a significant method to improve the catalytic activity.However,precisely controllable phase engineering of MoSe_(2) has rarely been reported.Herein,by in situ Li ions intercalation in MoSe_(2),a precisely controllable phase evolution from 2H-MoSe_(2) to 1T-MoSe_(2) was realized.More importantly,the definite functional relationship between cut-off voltage and phase structure was first identified for phase engineering through in situ observation and modulation methods.The sulfur host(CNFs/1T-MoSe_(2))presents high charge density,strong polysulfides adsorption,and catalytic kinetics.Moreover,Li-S cells based on it display capacity retention of 875.3mAh g^(-1) after 500 cycles at 1 C and an areal capacity of 8.71mAh cm^(-2) even at a high sulfur loading of 8.47mg cm^(-2).Furthermore,the flexible pouch cell exhibiting decent performance will endow a promising potential in the wearable energy storage field.This study proposes an effective strategy to precisely control the phase structure of MoSe_(2),which may provide the reference to fabricate the highly efficient electrocatalysts for LSBs and other energy systems.
基金support from the National Key Research and Development Program of China (No.2020YFA0907300)the National Natural Science Foundation of China (No.22077069)+1 种基金the Natural Science Foundation of Tianjin (19JCZDJC33400)the Fundamental Research Funds for the Central Universities,Nankai University (63201111).
文摘The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.
基金the support from National Natural Science Foundation of China (22208355, 22178363 and 21978300)the financial support and mica samples from Changzi Wu and RIKA technology CO., LTD.
文摘The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.
基金supported by the National Natural Science Foundation of China(Grant Nos.21972068,21875112,and 22075290)the Nanjing IPE Institute of Green Manufacturing Industrythe Beijing Natural Science Foundation(Grant No.Z200012).
文摘The development of economical,efficient,and robust electrocatalysts toward the hydrogen evolution reaction(HER)is highly imperative for the rapid advancement of renewable H2 energy-associated technologies.Extensive utilization of the heterointerface effect can endow the catalysts with remarkably boosted electrocatalytic performance due to the modified electronic state of active sites.Herein,we demonstrate deliberate crafting of CoP/CoO heterojunction porous nanotubes(abbreviated as CoP/CoO PNTs hereafter)using a self-sacrificial template-engaged strategy.Precise control over the Kirkendall diffusion process of the presynthesized cobalt–aspartic acid complex nanowires is indispensable for the formation of CoP/CoO heterostructures.The topochemical transformation strategy of the reactive templates enables uniform and maximized construction of CoP/CoO heterojunctions throughout all the porous nanotubes.The establishment of CoP/CoO heterojunctions could considerably modify the electronic configuration of the active sites and also improve the electric conductivity,which endows the resultant CoP/CoO PNTs with enhanced intrinsic activity.Simultaneously,the hollow and porous nanotube architectures allow sufficient accessibility of exterior/interior surfaces and molecular permeability,drastically promoting the reaction kinetics.Consequently,when used as HER electrocatalysts,the well-designed CoP/CoO PNTs show Pt-like activity,with an overpotential of only 61 mV at 10mA cm^(−2) and excellent stability in 1.0M KOH medium,exceeding those of the vast majority of the previously reported nonprecious candidates.Density functional theory calculations further substantiate that the construction of CoP/CoO heterojunctions enables optimization of the Gibbs free energies for water adsorption and H adsorption,resulting in boosted HER intrinsic activity.The present study may provide in-depth insights into the fundamental mechanisms of heterojunction-induced electronic regulation,which may pave the way for the rational design of advanced Earth-abundant electrocatalysts in the future.
基金the support of the National Key Research and Development Program of China(2021YFB4000505)Sichuan Science and Technology Program(2021YFS0301)。
文摘Accidents in chemical production usually result in fatal injury,economic loss and negative social impact.Chemical accident reports which record past accident information,contain a large amount of expert knowledge.However,manually finding out the key factors causing accidents needs reading and analyzing of numerous accident reports,which is time-consuming and labor intensive.Herein,in this paper,a semiautomatic method based on natural language process(NLP)technology is developed to construct a knowledge graph of chemical accidents.Firstly,we build a named entity recognition(NER)model using SoftLexicon(simplify the usage of lexicon)+BERT-Transformer-CRF(conditional random field)to automatically extract the accident information and risk factors.The risk factors leading to accident in chemical accident reports are divided into five categories:human,machine,material,management,and environment.Through analysis of the extraction results of different chemical industries and different accident types,corresponding accident prevention suggestions are given.Secondly,based on the definition of classes and hierarchies of information in chemical accident reports,the seven-step method developed at Stanford University is used to construct the ontology-based chemical accident knowledge description model.Finally,the ontology knowledge description model is imported into the graph database Neo4j,and the knowledge graph is constructed to realize the structu red storage of chemical accident knowledge.In the case of information extraction from 290 Chinese chemical accident reports,SoftLexicon+BERT-Transformer-CRF shows the best extraction performance among nine experimental models.Demonstrating that the method developed in the current work can be a promising tool in obtaining the factors causing accidents,which contributes to intelligent accident analysis and auxiliary accident prevention.
基金partially supported by the Major Program of the National Natural Science Foundation of China(No.22090034)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the pursuit of higher energy density.However,it suffers from serious structural degradation and surface side reactions,in particular,at the voltage above 4.60 V,leading to rapid decay of the battery life.Taking into account the desirable oxygen buffering property and the fast ion mobility characteristic of cerium oxide fluoride,in this work,we prepared Ce&F co-modified LiCoO_(2)by using the precursors of Ce(NO_(3))_(3)·6H_(2)O and NH_(4)F,and evaluated the electrochemical performance under voltages exceeding 4.60 V.The results indicated that the modified samples have multiphase heterostructure of surface CeO_(2-x)and unique Ce-O-F solid solution phase.At 3.0–4.60 V and 25℃,the preferred sample LCO-0.5Ce-0.3F has a high initial discharge specific capacity of 221.9 mA h g^(-1)at 0.1 C,with the retention of 80.3%and 89.6%after 300 cycles at 1 and 5 C,comparing with the pristine LCO(56.4%and 22.6%).And at 3.0–4.65 V,its retention is 64.0%after 300 cycles at 1 C,versus 8.5%of the pristine LCO.Through structural characterizations and DFT calculations,it suggests that Ce^(4+)&F^(-)co-doping suppresses the H3 to H1/3 irreversible phase transition,stabilizes the lattice structure,and reduces the redox activity of the lattice oxygen by modulating the Co 3d–O 2p energy band,consequently improving the electrochemical performance of LiCoO_(2)at high voltages.
基金partially supported by the Major Program of the National Natural Science Foundation of China (No.22090034)the Haihe Laboratory of Sustainable Chemical Transformations for financial support (CYZC202108)
文摘A sol-gel tandem with a solid-phase modification procedure was developed to synthesize Li_(2)TiO_(3)-doped LiCoO_(2) together with phosphate coatings(denoted as LCO-Ti/P),which possesses excellent high-voltage performance in the range of 3.0-4.6 V.The characterizations of X-ray diffraction,high-resolution transmission electron microscopy,and X-ray photoelectron spectroscopy illustrated that the modified sample LCO-Ti/P had the dopant of monoclinic Li_(2)TiO_(3) and amorphous Li3PO4 coating layers.LCO-Ti/P has an initial discharge capacity of 211.6 mAh/g at 0.1 C and a retention of 85.7%after 100 cycles at 1 C and 25±1°C between 3.0 and 4.6 V.Nyquist plots reflect that the charge transfer resistance of LCO-Ti/P after 100 cycles at 1 C is much lower than that of the spent LCO,which benefits Li-ion diffusion.Density functional theory calculations disclose the superior lattice-matching property of major crystal planes for Li_(2)TiO_(3) and LiCoO_(2),the lower energy barriers for Li-ion diffusion in Li_(2)TiO_(3),and the suppressed oxygen release performance resulting from phosphate adsorption.This work provides useful guidance on the rational design of the high-voltage performance of modified LiCoO_(2) materials in terms of lattice-matching properties aside from the phosphate coating to reduce the energy barriers of Li-ion diffusion and enhance cycling stability.
基金the financial support of the Training Program of the Major Research Plan of the National Natural Science Foundation of China(92061124)the National Natural Science Foundation of China(21975292,21978331,22068008,and 52101186)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2021A1515010167 and 2022A1515011196)the Guangzhou Key R&D Program/Plan Unveiled Flagship Project(20220602JBGS02)the Guangzhou Basic and Applied Basic Research Project(202201011449)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202220 and FC202216)。
文摘Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.
基金supported by the Australian Research Council under the ARC Laureate Fellowship program(FL170100101)。
文摘Orthorhombic molybdenum trioxide(α-MoO_(3)) electrode material experiences severe capacity fading and poor cycling stability in aqueous electrolytes.We investigated the charge-storage performance of α-MoO_(3) electrode in aluminium trifluoromethanesulfonate(Al(OTf)_(3))-based salt-in-water electrolyte(SiWE) and water-in-salt electrolyte(WiSE).It was found that α-MoO_(3) electrode exhibits significantly different cycling stabilities in both electrolytes with capacity retentions of 8% using the former and87% using the latter.This is because α-MoO_(3) electrode maintains its crystal structure upon cycling in WiSE,but experiences substantial structural collapses and partial dissolution upon cycling in SiWE.This behaviour was inferred from both operando electrogravimetry and ex situ analyses.Research results suggest that the predominant charge-storage mechanism in a-MoO_(3) electrode using WiSE is the intercalation of protons produced from electrolyte hydrolysis with some contribution from surface pseudocapacitance enabled by Al3+ions.A two-volt full cell fabricated from α-MoO_(3) electrode as anode and copper hexacyanoferrate(CuHCF) electrode as cathode using WiSE delivers volumetric and gravimetric energies of 10.4 Wh/L and 26.5 Wh/kg,respectively,with 78% capacity retention after 2500 cycles.This study provides an insightful understanding of the electrochemical performance of α-MoO_(3) electrode in Al(OTf)_(3)-based electrolytes.
基金the National Research Foundation(NRF)of Korea(No.2022R1A2B5B02002097),funded by the Korea government(MSIT).
文摘Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery damage or fracture is a critical concern.Water-based(aqueous)electrolytes have been receiving attention as an alternative to organic electrolytes.However,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous electrolytes.Therefore,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains challenging.This Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the electrolytes.These aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the electrolytes.In addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.
基金supported by the National Natural Science Funds(No.21878226)Innovative Research Group Project of the National Natural Science Foundation of China(No.22121004)。
文摘Atomically dispersed metal sites(ADMSs)play key roles in electrochemical energy conversion.The covalent organic frameworks(COFs)enable the precise control of the chemical compositions and structures at the molecular level,making them ideal substrates for supporting ADMSs.In this review,we systematically summarize the recent progress on the design and synthesis of ADMSs in COFs,including embedding molecular catalysts into COFs,immobilizing ADMSs on heteroatom-containing COFs,and preparing COF-derived carbon materials through pyrolysis.The electrocatalytic performance of the resulting catalysts is presented for various electrochemical reactions,involving oxygen reduction reaction(ORR),carbon dioxide reduction reaction(CO_(2)RR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and nitrogen reduction reaction(NRR).The modulation strategies of AMDSs in COFs for enhanced activity,selectivity,and stability are highlighted,together with a perspective of the current challenges and the future opportunities in this field.
