Fabrication of single atom catalysts(SACs)by a green and gentle method is important for their practical Fenton-like use.In this work,a high effective iron-based catalyst was prepared from the iron-rich Enteromorpha fo...Fabrication of single atom catalysts(SACs)by a green and gentle method is important for their practical Fenton-like use.In this work,a high effective iron-based catalyst was prepared from the iron-rich Enteromorpha for NPX degradation via peroxymonosulfate(PMS).Both Fe-SACs and iron-clusters was fabricated from the intrinsic iron element in Enteromorpha after the urea saturation.The Fe-SACs/clusters can achieve 100%of NPX oxidation within 20 min with the k_(obs)of 0.282 min^(-1).Quenching tests indicated that the radical pathways were not dominated in the catalytic systems,and strong electron transfer process can be induced in the Fe-SACs/clusters+PMS system by using the NPX as electron donor and FeSACs/clusters/PMS^*complexes as electron acceptor.This result was consistent with the phenomenon observed in the galvanic oxidation system.In addition,the Fe-SACs/clusters was deposited onto the ceramic membrane(CM)by the spraying-crosslinking process to form a Fe-SACs/clusters@CM,which showed an effective and continuous NPX degradation in a heterogeneous PMS system.展开更多
Phase manipulation of MoS_(2) from thermodynamically stable 2H phase to the unstable but more reactive 1T phase represents a crucial strategy for improving the reactivity in many reactions.The widely adopted wet chemi...Phase manipulation of MoS_(2) from thermodynamically stable 2H phase to the unstable but more reactive 1T phase represents a crucial strategy for improving the reactivity in many reactions.The widely adopted wet chemistry approach uses intercalating entities especially alkali metal ions to achieve the phase transition;however,these entities are normally inert for the target reaction.Here,we describe the first use of iron atoms for the intercalation of 2H-MoS_(2) layers,driving the partial transition from 2H to 1T phase.Interestingly,in the peroxymonosulfate(PMS)-based Fenton-like reactions,the interlayered confinement of Fe atoms not only activates the inert basal plane,but also adds more reactive Fe sites for the formation of metal-PMS complex as primary reactive species for pollutant removal.In the degradation of a model pollutant carbamazepine(CBZ),the Fe-intercalated MoS_(2) exhibits a first order rate constant 13.3 times higher than 2H-MoS_(2).This strategy is a new direction for manipulating the phase composition and boosting the catalytic reactivity of MoS_(2)-based catalysts in various scenarios,including environmental remediation and energy applications.展开更多
In this work,Fe_(3)O_(4) nanoparticles(NPs)loaded inside and outside halloysite nanotubes(HNTs)were prepared and developed as the heterogeneous Fenton-like catalysts for the removal of representative organic pollutant...In this work,Fe_(3)O_(4) nanoparticles(NPs)loaded inside and outside halloysite nanotubes(HNTs)were prepared and developed as the heterogeneous Fenton-like catalysts for the removal of representative organic pollutants.Characterization results indicated that the samples with Fe_(3)O_(4) NPs loaded outside the HNTs lumen(Fe_(3)O_(4)/HNTs)and inside the HNTs lumen(Fe_(3)O_(4)@HNTs)were successfully prepared.Both samples had typical magnetic hysteresis loops,while Fe_(3)O_(4)@HNTs exhibited higher magnetization intensity.The comparative experiments showed that Fe_(3)O_(4)@HNTs had better Fenton-like catalytic ability than that of Fe_(3)O_(4)/HNTs in the degradation of various organic pollutants.Taking Rhodamine B(RhB)as an example,the adsorption thermodynamics and kinetics of RhB onto Fe_(3)O_(4)/HNTs and Fe_(3)O_(4)@HNTs were also investigated.The comparative results demonstrated that the adsorption ability of Fe_(3)O_(4)/HNTs was better than that of Fe_(3)O_(4)@HNTs.Moreover,the dissolved concentration of Fe^(2+)and production amount of hydroxyl radical(·OH)in the Fe_(3)O_(4)@HNTs-H_(2)O_(2) system were significantly higher than those in the Fe_(3)O_(4)/HNTs-H_(2)O_(2) system.Based on aforementioned comparison,the nano-confinement effect in the Fe_(3)O_(4)@HNTs-H_(2)O_(2) system was verified.This work provides meaningful guidance for the cheap and convenient design of nanoreactors for Fenton-like applications.展开更多
Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fe...Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.展开更多
The Fenton-like process shows promising potential to generate reactive oxygen species for the reme-diation of increasingly environmental pollutants.However,the slow development of high-activity cata-lysts with strong ...The Fenton-like process shows promising potential to generate reactive oxygen species for the reme-diation of increasingly environmental pollutants.However,the slow development of high-activity cata-lysts with strong stability and low leaching of metal ions has greatly inhibited scale-up application of this technology.Here,cobalt(Co)/nitrogen(N)atom co-curved carbon nanorod(CoNC)containing highly uniform CoN_(x)active sites is developed as a Fenton-like catalyst for the effective catalytic oxidation of various organics via peroxymonosulfate(PMS)activation with high stability.As confirmed by the exper-imental results,singlet oxygen(^(1)O_(2))is the dominant active species for the degradation of the organ-ics,with a proportion of 100%.Furthermore,density functional theory calculations indicate that CoN_(2)C_(2)is the most effective ligand structure with more negative adsorption energy for PMS and the shortest length Co-O bond,while the most reasonable generation pathway for^(1)O_(2)was CoN_(2)C_(2)-PMS→CoN_(2)C_(2)-OH∗→2O∗→^(1)O_(2).Further studies demonstrate that the electron can be transferred from the highest occupied molecular orbitals of the organics to the lowest unoccupied molecular orbitals of the PMS via CoN_(2)C_(2)action.In addition,the CoNC presents strong resistance to inorganic ions and natural organic matter in the Fenton-like catalysis process.The presence of CoN_(2)C_(2)active centre can significantly shorten the migration distance of the^(1)O_(2)generated from PMS activation,which further enhances the Fenton-like catalytic activity in terms of mineralising various organic contaminants with high efficiency over a wide pH range.展开更多
In the pursuit of heterogeneous catalysts with high reactivity,metal organic framework(MOF)nanomaterials have received tremendous attentions.However,many MOF catalysts especially Fe-based MOFs need to be utilized imme...In the pursuit of heterogeneous catalysts with high reactivity,metal organic framework(MOF)nanomaterials have received tremendous attentions.However,many MOF catalysts especially Fe-based MOFs need to be utilized immediately after synthesis or being activated using high temperature,because of the easy loss of reactivity in humid environments resulting from the occupation of active Fe sites by water molecules.Here,we describe an inspiring strategy of growing MIL-101-Fe nanoparticles inside the three-dimensional confined space of graphene aerogel(GA),generating shapeable GA/MIL-101-Fe nanocomposite convenient for practical use.Compared to MIL-101-Fe,GA/MIL-101-Fe as catalyst demonstrates much higher reactivity in Fenton-like reaction,attributing to smaller MIL-101-Fe particle size,presence of active Fe(II)sites,and abundant defects in GA.Strikingly,the weakly hydrophobic nature of the composite greatly inhibits the loss of catalytic reactivity after being stored in humid air and accelerates the recovery of reactivity in mild temperature,by resisting the entrance of water molecules and helping to exclude water molecules.This work demonstrates that a delicate design of nanocomposite structure could not only improve the reactivity of the catalytic component,but also overcome its intrinsic drawback by taking advantage of the properties of host.We hope this functional nanoconfinement strategy could be extended to more scenarios in other fields.展开更多
Fabrication of multifunctional nanoplatform to in situ monitor Fenton reaction is of vital importance to probe the underlying reaction process and design high-performance catalyst. Herein, a hybrid catalyst comprising...Fabrication of multifunctional nanoplatform to in situ monitor Fenton reaction is of vital importance to probe the underlying reaction process and design high-performance catalyst. Herein, a hybrid catalyst comprising of single-crystalline Au nanoparticles (SC Au NPs) on reduced graphene oxide (RGO) sheet was prepared, which not only exhibited an excellent ^(1)O_(2) mediated Fenton-like catalytic activity in promoting rhodamine 6G (R6G) degradation by activating H_(2)O_(2), but also displayed a sensitive surface-enhanced Raman spectroscopy (SERS) detection performance to R6G with a linear response range from 1.0×10^(-8) mol/L to 1.0×10^(-5) mol/L thus providing a powerful and versatile nanoplatform for in situ SERS monitoring Fenton-like catalytic reaction. The integration of catalytic and SERS activities into a single nanostructure are expected to provide great potentials for practical applications in environmental catalysis.展开更多
Identifying the active site of oxide-supported metal catalysts and revealing the intrinsic synergistic mechanism between metal and oxide support remain a large challenge.Herein,we report the identification and separat...Identifying the active site of oxide-supported metal catalysts and revealing the intrinsic synergistic mechanism between metal and oxide support remain a large challenge.Herein,we report the identification and separation of the Pt-O-Ti interface and TiO_(2) surface in Pt-TiO_(2)-based catalysts by depositing different thickness of TiO_(2) shell with∼0.4-nm micropores onto the surface of Pt/TiO_(2) catalyst through atomic layer deposition(ALD).In the oxidation of 3,3′,5,5′-tetramethylbenzidine(TMB)by hydrogen peroxide(H_(2)O_(2))process,the TiO_(2) microporous shells can prevent the contact between TMB and embedded Pt clusters,but not delay the diffusion of H_(2)O_(2).The heterolysis of H_(2)O_(2) to ·OH occurs on the Pt-O-Ti interface,and the generated•OH migrates to the TiO_(2) surface to supplement the surface lattice oxygen,which sequentially oxidizes TMB to oxTMB.And the synergistic effect between Pt-O-Ti interface active sties and TiO_(2) surface active sites can significantly improve the catalytic performance.Our study provides a guide for the understanding of the intrinsic synergistic mechanism between the metal and oxide support in the metal-oxide catalysts.展开更多
As other natural iron-bearing minerals, schorl could be taken as an effective iron source for degradation of organic pollutants by mineral-catalyzed Fenton-like system. In our present study, the schorl-catalyzed Fento...As other natural iron-bearing minerals, schorl could be taken as an effective iron source for degradation of organic pollutants by mineral-catalyzed Fenton-like system. In our present study, the schorl-catalyzed Fenton-like system has been successfully developed for discoloration of an active commercial dye, Rhodamine B (RhB), in an aqueous solution. Through a number of batch discoloration experiments under various conditions, it was found that the reactivity of the system increased by, respectively, increasing schorl dosage, temperature, hydrogen peroxide starting concentration and by decreasing the pH. Over 90% of discoloration ratio could be gained in less than 30 min, and nearly 70% of total organic carbon (TOC) could be removed in less than 200 min. And, the schorl catalyst could be repeatedly used at least ten times, still with high catalytic activity. Comparative studies indicated that the RhB discoloration ratios were much higher in presence of schorl and H2O2 than those in presence of schorl or H2O2 only, which suggested that the schorl-catalyzed Fenton-like reaction governed the RhB discoloration process. The content of Fe ion leaching in the solution was also measured using inductively coupling plasma-atomic emission spectra (ICP-AES). A mechanism proposed herein suggested that adsorption and Fenton-like reaction (heterogeneous and homogeneous) were responsible for the discoloration of RhB.展开更多
A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photo...A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photocatalysis（Vis-Photo）, for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B（Rh B） degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2＋was found.展开更多
The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct ...The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.展开更多
High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion te...High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for efficient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm^(-2)at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excellent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved electrocatalytic reaction mechanism for the in-situ generated nickel–iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced catalytic activity and durability.These findings provide promising strategies for the rational design of nonnoble metal OER catalysts.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
In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic solutions.Experimental results demonstrate a rectangular hyperbo...In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic solutions.Experimental results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant value.We consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant value.This could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the catalyst.Our study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.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 increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking process.In this study,the interaction between calcium carbonate and iron or...The increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking process.In this study,the interaction between calcium carbonate and iron ore powder and the mineralization mechanism of fluxed iron ore pellet in the roasting process were investigated through diffusion couple experiments.Scanning electron microscopy with energy dispersive spectroscopy was used to study the elements’diffusion and phase transformation during the roasting process.The results indicated that limestone decomposed into calcium oxide,and magnetite was oxidized to hematite at the early stage of preheating.With the increase in roasting temperature,the diffusion rate of Fe and Ca was obviously accelerated,while the diffusion rate of Si was relatively slow.The order of magnitude of interdiffusion coefficient of Fe_(2)O_(3)-CaO diffusion couple was 10^(−10) m^(2)·s^(−1) at a roasting temperature of 1200℃for 9 h.Ca_(2)Fe_(2)O_(5) was the initial product in the Fe_(2)O_(3)-CaO-SiO_(2) diffusion interface,and then Ca_(2)Fe_(2)O_(5) continued to react with Fe_(2)O_(3) to form CaFe_(2)O_(4).With the expansion of the diffusion region,the sillico-ferrite of calcium liquid phase was produced due to the melting of SiO_(2) into CaFe_(2)O_(4),which can strengthen the consolidation of fluxed pellets.Furthermore,andradite would be formed around a small part of quartz particles,which is also conducive to the consolidation of fluxed pellets.In addition,the principle diagram of limestone and quartz diffusion reaction in the process of fluxed pellet roasting was discussed.展开更多
This work investigated the pyrolysis reaction of waste resin in a fluidized bed reactor.It was found that the pyrolysis-generated ash would adhere to the surface of ceramic particles,causing particle agglomeration and...This work investigated the pyrolysis reaction of waste resin in a fluidized bed reactor.It was found that the pyrolysis-generated ash would adhere to the surface of ceramic particles,causing particle agglomeration and defluidization.Adding kaolin could effectively inhibit the particle agglomeration during the fluidized pyrolysis reaction through physical isolation and chemical reaction.On the one hand,kaolin could form a coating layer on the surface of ceramic particles to prevent the adhesion of organic ash generated by the pyrolysis of resin.On the other hand,when a sufficient amount of kaolin(-0.2%(mass))was added,the activated kaolin could fully contact with the Na+ ions generated by the pyrolysis of resin and react to form a high-melting aluminosilicate mineral(nepheline),which could reduce the formation of low-melting-point sodium sulfate and thereby avoid the agglomeration of ceramic particles.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 metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and...The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting process.Therefore,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is necessary.In the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild steel.Meanwhile,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and AZ91D.AlFe_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg matrix.It is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction process.By measuring the thickness of different layers,the growth constant was calculated.It increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.展开更多
基金supported by National Natural Science Foundation of China(No.52170086)Shandong Provincial Excellent Youth(No.ZR2022YQ47)。
文摘Fabrication of single atom catalysts(SACs)by a green and gentle method is important for their practical Fenton-like use.In this work,a high effective iron-based catalyst was prepared from the iron-rich Enteromorpha for NPX degradation via peroxymonosulfate(PMS).Both Fe-SACs and iron-clusters was fabricated from the intrinsic iron element in Enteromorpha after the urea saturation.The Fe-SACs/clusters can achieve 100%of NPX oxidation within 20 min with the k_(obs)of 0.282 min^(-1).Quenching tests indicated that the radical pathways were not dominated in the catalytic systems,and strong electron transfer process can be induced in the Fe-SACs/clusters+PMS system by using the NPX as electron donor and FeSACs/clusters/PMS^*complexes as electron acceptor.This result was consistent with the phenomenon observed in the galvanic oxidation system.In addition,the Fe-SACs/clusters was deposited onto the ceramic membrane(CM)by the spraying-crosslinking process to form a Fe-SACs/clusters@CM,which showed an effective and continuous NPX degradation in a heterogeneous PMS system.
基金support from the National Natural Science Foundation of China(Nos.22276095,22106071,and 81801029)the Natural Science Foundation of Jiangsu Province(Nos.BK20211522 and BK20200504)the Project of Jiangsu Provincial Commission of Health(No.M2022060).We gratefully acknowledge HZWTECH for providing computation facilities.
文摘Phase manipulation of MoS_(2) from thermodynamically stable 2H phase to the unstable but more reactive 1T phase represents a crucial strategy for improving the reactivity in many reactions.The widely adopted wet chemistry approach uses intercalating entities especially alkali metal ions to achieve the phase transition;however,these entities are normally inert for the target reaction.Here,we describe the first use of iron atoms for the intercalation of 2H-MoS_(2) layers,driving the partial transition from 2H to 1T phase.Interestingly,in the peroxymonosulfate(PMS)-based Fenton-like reactions,the interlayered confinement of Fe atoms not only activates the inert basal plane,but also adds more reactive Fe sites for the formation of metal-PMS complex as primary reactive species for pollutant removal.In the degradation of a model pollutant carbamazepine(CBZ),the Fe-intercalated MoS_(2) exhibits a first order rate constant 13.3 times higher than 2H-MoS_(2).This strategy is a new direction for manipulating the phase composition and boosting the catalytic reactivity of MoS_(2)-based catalysts in various scenarios,including environmental remediation and energy applications.
基金supported by the Natural Science Foundation of Heilongjiang Province,China(Grant No.LH2022E083).
文摘In this work,Fe_(3)O_(4) nanoparticles(NPs)loaded inside and outside halloysite nanotubes(HNTs)were prepared and developed as the heterogeneous Fenton-like catalysts for the removal of representative organic pollutants.Characterization results indicated that the samples with Fe_(3)O_(4) NPs loaded outside the HNTs lumen(Fe_(3)O_(4)/HNTs)and inside the HNTs lumen(Fe_(3)O_(4)@HNTs)were successfully prepared.Both samples had typical magnetic hysteresis loops,while Fe_(3)O_(4)@HNTs exhibited higher magnetization intensity.The comparative experiments showed that Fe_(3)O_(4)@HNTs had better Fenton-like catalytic ability than that of Fe_(3)O_(4)/HNTs in the degradation of various organic pollutants.Taking Rhodamine B(RhB)as an example,the adsorption thermodynamics and kinetics of RhB onto Fe_(3)O_(4)/HNTs and Fe_(3)O_(4)@HNTs were also investigated.The comparative results demonstrated that the adsorption ability of Fe_(3)O_(4)/HNTs was better than that of Fe_(3)O_(4)@HNTs.Moreover,the dissolved concentration of Fe^(2+)and production amount of hydroxyl radical(·OH)in the Fe_(3)O_(4)@HNTs-H_(2)O_(2) system were significantly higher than those in the Fe_(3)O_(4)/HNTs-H_(2)O_(2) system.Based on aforementioned comparison,the nano-confinement effect in the Fe_(3)O_(4)@HNTs-H_(2)O_(2) system was verified.This work provides meaningful guidance for the cheap and convenient design of nanoreactors for Fenton-like applications.
基金supported by the Program for the National Natural Science Foundation of China(52070077,51879101,51779090)the National Program for Support of Top-Notch Young Professionals of China(2014)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(IRT-13R17)Natural Science Foundation of Hunan Province(2022JJ20013,2021JJ40098).
文摘Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.
基金This work was financially supported from the Key Program of National Natural Science Foundation of China(No.42030713)the National Natural Science Foundation of China(No.42007358)+4 种基金the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515110518 and2021A1515110369)the Hongkong Schol-arship Program(No.XJ2020059)the China Postdoctoral Sci-ence Foundation(No.2019M663382)the Ministry of Science and Technology of China for State Key Research and Development Project(No.2016YFC0400702)the YoungInnovativeTalent Project of Guangdong Provincial Department of Education(No.2019GKQNCX056).The authors would like to thank Shiyanjia Lab(www.shiyanjia.com)for the GC-MS measurements.
文摘The Fenton-like process shows promising potential to generate reactive oxygen species for the reme-diation of increasingly environmental pollutants.However,the slow development of high-activity cata-lysts with strong stability and low leaching of metal ions has greatly inhibited scale-up application of this technology.Here,cobalt(Co)/nitrogen(N)atom co-curved carbon nanorod(CoNC)containing highly uniform CoN_(x)active sites is developed as a Fenton-like catalyst for the effective catalytic oxidation of various organics via peroxymonosulfate(PMS)activation with high stability.As confirmed by the exper-imental results,singlet oxygen(^(1)O_(2))is the dominant active species for the degradation of the organ-ics,with a proportion of 100%.Furthermore,density functional theory calculations indicate that CoN_(2)C_(2)is the most effective ligand structure with more negative adsorption energy for PMS and the shortest length Co-O bond,while the most reasonable generation pathway for^(1)O_(2)was CoN_(2)C_(2)-PMS→CoN_(2)C_(2)-OH∗→2O∗→^(1)O_(2).Further studies demonstrate that the electron can be transferred from the highest occupied molecular orbitals of the organics to the lowest unoccupied molecular orbitals of the PMS via CoN_(2)C_(2)action.In addition,the CoNC presents strong resistance to inorganic ions and natural organic matter in the Fenton-like catalysis process.The presence of CoN_(2)C_(2)active centre can significantly shorten the migration distance of the^(1)O_(2)generated from PMS activation,which further enhances the Fenton-like catalytic activity in terms of mineralising various organic contaminants with high efficiency over a wide pH range.
基金The authors thanked the financial support from the National Natural Science Foundation of China(No.21925602)Natural Science Foundation of Jiangsu Province(No.BK20201309)the Fundamental Research Funds for the Central Universities(No.30920021116).
文摘In the pursuit of heterogeneous catalysts with high reactivity,metal organic framework(MOF)nanomaterials have received tremendous attentions.However,many MOF catalysts especially Fe-based MOFs need to be utilized immediately after synthesis or being activated using high temperature,because of the easy loss of reactivity in humid environments resulting from the occupation of active Fe sites by water molecules.Here,we describe an inspiring strategy of growing MIL-101-Fe nanoparticles inside the three-dimensional confined space of graphene aerogel(GA),generating shapeable GA/MIL-101-Fe nanocomposite convenient for practical use.Compared to MIL-101-Fe,GA/MIL-101-Fe as catalyst demonstrates much higher reactivity in Fenton-like reaction,attributing to smaller MIL-101-Fe particle size,presence of active Fe(II)sites,and abundant defects in GA.Strikingly,the weakly hydrophobic nature of the composite greatly inhibits the loss of catalytic reactivity after being stored in humid air and accelerates the recovery of reactivity in mild temperature,by resisting the entrance of water molecules and helping to exclude water molecules.This work demonstrates that a delicate design of nanocomposite structure could not only improve the reactivity of the catalytic component,but also overcome its intrinsic drawback by taking advantage of the properties of host.We hope this functional nanoconfinement strategy could be extended to more scenarios in other fields.
基金supported by the National Natural Science Foundation of China (Nos. 21577156, 21876184)the Fundamental Research Funds for the Central University (No. 310421124)。
文摘Fabrication of multifunctional nanoplatform to in situ monitor Fenton reaction is of vital importance to probe the underlying reaction process and design high-performance catalyst. Herein, a hybrid catalyst comprising of single-crystalline Au nanoparticles (SC Au NPs) on reduced graphene oxide (RGO) sheet was prepared, which not only exhibited an excellent ^(1)O_(2) mediated Fenton-like catalytic activity in promoting rhodamine 6G (R6G) degradation by activating H_(2)O_(2), but also displayed a sensitive surface-enhanced Raman spectroscopy (SERS) detection performance to R6G with a linear response range from 1.0×10^(-8) mol/L to 1.0×10^(-5) mol/L thus providing a powerful and versatile nanoplatform for in situ SERS monitoring Fenton-like catalytic reaction. The integration of catalytic and SERS activities into a single nanostructure are expected to provide great potentials for practical applications in environmental catalysis.
基金financially supported from the National Natural Science Foundation of China(21802094,22272127,22002118,and 22172119)the National Science Fund for Distinguished Young Scholars(21825204)+1 种基金the Fundamental Research Funds for the Central Universities(D5000210666)the Natural Science Basic Research Plan in Shaanxi Province of China(2021JM-047).
文摘Identifying the active site of oxide-supported metal catalysts and revealing the intrinsic synergistic mechanism between metal and oxide support remain a large challenge.Herein,we report the identification and separation of the Pt-O-Ti interface and TiO_(2) surface in Pt-TiO_(2)-based catalysts by depositing different thickness of TiO_(2) shell with∼0.4-nm micropores onto the surface of Pt/TiO_(2) catalyst through atomic layer deposition(ALD).In the oxidation of 3,3′,5,5′-tetramethylbenzidine(TMB)by hydrogen peroxide(H_(2)O_(2))process,the TiO_(2) microporous shells can prevent the contact between TMB and embedded Pt clusters,but not delay the diffusion of H_(2)O_(2).The heterolysis of H_(2)O_(2) to ·OH occurs on the Pt-O-Ti interface,and the generated•OH migrates to the TiO_(2) surface to supplement the surface lattice oxygen,which sequentially oxidizes TMB to oxTMB.And the synergistic effect between Pt-O-Ti interface active sties and TiO_(2) surface active sites can significantly improve the catalytic performance.Our study provides a guide for the understanding of the intrinsic synergistic mechanism between the metal and oxide support in the metal-oxide catalysts.
基金Supported by Heilongjiang Science Fundation for Young Scholars (Grant No. QC07C02)Scientific Foundation of Heilongjiang Education Department, China (Grant No. 11531035)
文摘As other natural iron-bearing minerals, schorl could be taken as an effective iron source for degradation of organic pollutants by mineral-catalyzed Fenton-like system. In our present study, the schorl-catalyzed Fenton-like system has been successfully developed for discoloration of an active commercial dye, Rhodamine B (RhB), in an aqueous solution. Through a number of batch discoloration experiments under various conditions, it was found that the reactivity of the system increased by, respectively, increasing schorl dosage, temperature, hydrogen peroxide starting concentration and by decreasing the pH. Over 90% of discoloration ratio could be gained in less than 30 min, and nearly 70% of total organic carbon (TOC) could be removed in less than 200 min. And, the schorl catalyst could be repeatedly used at least ten times, still with high catalytic activity. Comparative studies indicated that the RhB discoloration ratios were much higher in presence of schorl and H2O2 than those in presence of schorl or H2O2 only, which suggested that the schorl-catalyzed Fenton-like reaction governed the RhB discoloration process. The content of Fe ion leaching in the solution was also measured using inductively coupling plasma-atomic emission spectra (ICP-AES). A mechanism proposed herein suggested that adsorption and Fenton-like reaction (heterogeneous and homogeneous) were responsible for the discoloration of RhB.
基金supported by the Fundamental Research Funds for the Central Universities(No.CDJXS12210002)the Major Project Foundation of Science and Technology Innovation in Minister of Education(No.708071)+2 种基金the Financial Supports of the National Natural Science Foundation of China(No.51108483)Natural Science Foundation Project of CQ CSTC(No.cstcjjA 20002)the 111 Project(No.B13041)
文摘A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photocatalysis（Vis-Photo）, for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B（Rh B） degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2＋was found.
基金supported by the Taishan Scholar Program of Shandong Province,China (tsqn202211162)the National Natural Science Foundation of China (22102079)the Natural Science Foundation of Shandong Province of China (ZR2021YQ10,ZR2022QB163)。
文摘The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.
基金the staff at Beamline (BL08U1-A and BL11B)of the Shanghai Synchrotron Radiation Facility (SSRF)the support from the National Key Research&Development Program of China (2022YFB3803700)+2 种基金the National Natural Science Foundation of China (52171186)the support through the Overseas Outstanding Youth Fund and Shanghai Pujiang Talent Project (21PJ1408500)the financial support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for efficient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm^(-2)at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excellent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved electrocatalytic reaction mechanism for the in-situ generated nickel–iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced catalytic activity and durability.These findings provide promising strategies for the rational design of nonnoble metal OER catalysts.
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supported by the National Natural Science Foundation of China(21972131)。
文摘In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic solutions.Experimental results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant value.We consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant value.This could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the catalyst.Our study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.
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support of Shanxi Province Major Science and Technology Projects,China (No.20191101002).
文摘The increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking process.In this study,the interaction between calcium carbonate and iron ore powder and the mineralization mechanism of fluxed iron ore pellet in the roasting process were investigated through diffusion couple experiments.Scanning electron microscopy with energy dispersive spectroscopy was used to study the elements’diffusion and phase transformation during the roasting process.The results indicated that limestone decomposed into calcium oxide,and magnetite was oxidized to hematite at the early stage of preheating.With the increase in roasting temperature,the diffusion rate of Fe and Ca was obviously accelerated,while the diffusion rate of Si was relatively slow.The order of magnitude of interdiffusion coefficient of Fe_(2)O_(3)-CaO diffusion couple was 10^(−10) m^(2)·s^(−1) at a roasting temperature of 1200℃for 9 h.Ca_(2)Fe_(2)O_(5) was the initial product in the Fe_(2)O_(3)-CaO-SiO_(2) diffusion interface,and then Ca_(2)Fe_(2)O_(5) continued to react with Fe_(2)O_(3) to form CaFe_(2)O_(4).With the expansion of the diffusion region,the sillico-ferrite of calcium liquid phase was produced due to the melting of SiO_(2) into CaFe_(2)O_(4),which can strengthen the consolidation of fluxed pellets.Furthermore,andradite would be formed around a small part of quartz particles,which is also conducive to the consolidation of fluxed pellets.In addition,the principle diagram of limestone and quartz diffusion reaction in the process of fluxed pellet roasting was discussed.
基金support and encouragement of the Joint Funds of the National Natural Science Foundation of China(No.U21B2095)the Major Research Project of National Natural Science Foundation of China(No.91834303).
文摘This work investigated the pyrolysis reaction of waste resin in a fluidized bed reactor.It was found that the pyrolysis-generated ash would adhere to the surface of ceramic particles,causing particle agglomeration and defluidization.Adding kaolin could effectively inhibit the particle agglomeration during the fluidized pyrolysis reaction through physical isolation and chemical reaction.On the one hand,kaolin could form a coating layer on the surface of ceramic particles to prevent the adhesion of organic ash generated by the pyrolysis of resin.On the other hand,when a sufficient amount of kaolin(-0.2%(mass))was added,the activated kaolin could fully contact with the Na+ ions generated by the pyrolysis of resin and react to form a high-melting aluminosilicate mineral(nepheline),which could reduce the formation of low-melting-point sodium sulfate and thereby avoid the agglomeration of ceramic particles.
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 Natural Science Foundation of Chongqing,China(Grant Nos.cstc2020jcyj-msxm X0544,CSTB2022NSCQ-MSX0352,CSTB2022NSCQ-MSX0891,cstc2020jcyj-msxm X0184)Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202001416)National Natural Science Foundation of China(Grant Nos.11847077,52001028)。
文摘The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting process.Therefore,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is necessary.In the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild steel.Meanwhile,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and AZ91D.AlFe_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg matrix.It is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction process.By measuring the thickness of different layers,the growth constant was calculated.It increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.
