Heteroatomic substitution and vacancy engineering of spinel oxides can theoretically optimize the oxygen evolution reaction(OER)through charge redistribution and d-band center modification but still remain a great cha...Heteroatomic substitution and vacancy engineering of spinel oxides can theoretically optimize the oxygen evolution reaction(OER)through charge redistribution and d-band center modification but still remain a great challenge in both the preparation and catalytic mechanism.Herein,we proposed a novel and efficient Ar-plasma(P)-assisted strategy to construct heteroatom Mo-substituted and oxygen vacancies enriched hierarchical spinel Co_(3)O_(4)porous nanoneedle arrays in situ grown on carbon cloth(denoted P-Mo-Co_(3)O_(4)@CC)to improve the OER performance.Ar-plasma technology can efficiently generate vacancy sites at the surface of hydroxide,which induces the anchoring of Mo anion salts through electrostatic interaction,finally facilitating the substitution of Mo atoms and the formation of oxygen vacancies on the Co_(3)O_(4)surface.The P-Mo-Co_(3)O_(4)@CC affords a low overpotential of only 276 mV at 10 mA cm^(−2)for the OER,which is 58 mV superior to that of Mo-free Co_(3)O_(4)@CC and surpasses commercial RuO_(2)catalyst.The robust stability and satisfactory selectivity(nearly 100%Faradic efficiency)of P-Mo-Co_(3)O_(4)@CC for the OER are also demonstrated.Theoreti-cal studies demonstrate that Mo with variable valance states can efficiently regulates the atomic ratio of Co^(3+)/Co^(2+)and increases the number of oxygen vacancies,thereby inducing charge redistribution and tuning the d-band center of Co_(3)O_(4),which improve the adsorption energy of oxygen intermediates(e.g.,*OOH)on P-Mo-Co_(3)O_(4)@CC during OER.Furthermore,the two-electrode OER//HER electrolyzer equipped with P-Mo-Co_(3)O_(4)@CC as anode displays a low operation potential of 1.54 V to deliver a current density of 10 mA cm^(−2),and also exhibits good reversibility and anticurrent fluctuation ability under simulated real energy supply conditions,demonstrating the great potential of P-Mo-Co_(3)O_(4)@CC in water electrolysis.展开更多
Urea oxidation reaction (UOR),which has favorable thermodynamic energy barriers compared with oxygen evolution reaction (OER),can provide more cost-effective electrons for the renewable energy systems,but is trapped b...Urea oxidation reaction (UOR),which has favorable thermodynamic energy barriers compared with oxygen evolution reaction (OER),can provide more cost-effective electrons for the renewable energy systems,but is trapped by its sluggish UOR kinetics and intricate reaction intermediates formation/desorption process.Herein,we report a novel and effective electrocatalyst consisting of carbon cloth supported nitrogen vacancies-enriched Ce-doped Ni_(3)N hierarchical nanosheets (Ce-Ni_(3)N @CC) to optimize the flat-footed UOR kinetics,especially the stiff rate-determine CO_(2)desorption step of UOR.Upon the introduction of valance state variable Ce,the resultant nitrogen vacancies enriched Ce-Ni_(3)N @CC exhibits an enhanced UOR performance where the operation voltage requires only 1.31 V to deliver the current density of 10 mA cm^(-2),which is superior to that of Ni_(3)N @CC catalyst (1.36 V) and other counterparts.Density functional theory (DFT) results demonstrate that the incorporation of Ce in Ni_(3)N lowers the formation energy of nitrogen vacancies,resulting in rich nitrogen vacancies in Ce-Ni_(3)N @CC.Moreover,the nitrogen vacancies together with Ce doping optimize the local charge distribution around Ni sites,and balance the adsorption energy of CO_(2)in the rate-determining step (RDS),as well as affect the initial adsorption structure of urea,leading to the superior UOR catalytic performance of Ce-Ni_(3)N @CC.When integrating the Ce-Ni_(3)N catalyst in UOR//HER and UOR//CO_(2)R flow electrolyzer,both of them perform well with low operation voltage and robust long-term stability,proofing that the thermodynamically favorable UOR can act as a suitable substitute anodic reaction compared with that of OER.Our findings here not only provide a novel UOR catalyst but also offer a promising design strategy for the future development of energy-related devices.展开更多
Modulating surface charge redistribution based on interface and defect engineering has been considered as a resultful means to boost electrocatalytic activity.However,the mechanism of synergistic regulation of heteroj...Modulating surface charge redistribution based on interface and defect engineering has been considered as a resultful means to boost electrocatalytic activity.However,the mechanism of synergistic regulation of heterojunction and vacancy defects remains unclear.Herein,a Vs-CoP-CoS_(2)/C n-n heterojunction with sulfur vacancies is successfully constructed,which manifests superior electrocatalytic activity for oxygen evolution,as demonstrated by a low overpotential of 170 mV to reach 10 mA/cm^(2).The experimental results and density functional theory calculations testify that the outstanding OER performance of Vs-CoP-CoS_(2)/C heterojunction is owed to the synergistic effect of sulfur vacancies and built-in electric field at n-n heterogeneous interface,which accelerates the electron transfer,induces the charge redistribution,and regulates the adsorption energy of active intermediates during the reaction.This study affords a promising means to regulate the electrocatalytic performance by the construction of heterogeneous interfaces and defects,and in-depth explores the synergistic mechanisms of n-n heterojunction and vacancies.展开更多
The basal planes of transition metal dichalcogenides are basically inert for catalysis due to the absence of adsorption and activation sites,which substantially limit their catalytic application.Herein,a facile strate...The basal planes of transition metal dichalcogenides are basically inert for catalysis due to the absence of adsorption and activation sites,which substantially limit their catalytic application.Herein,a facile strategy to activate the basal plane of WS_(2) for hydrogen evolution reaction(HER)catalysis by phosphorous-induced electron density modulation is demonstrated.The optimized P doped WS_(2)(P-WS_(2))nanowires arrays deliver a low overpotential of 88 mV at 10 mA·cm^(-2)with a Tafel slope of 62 mV·dec^(-1)for HER,which is substantially better than the pristine counterpart.X-ray photoelectron spectroscopy confirms the surface electron densities of WS_(2) have been availably manipulated by P doping.Moreover,density functional theory(DFT)studies further prove P doping can redistribute the density of states(DOS)around EF,which endow the inert basal plane of PWS_(2) with edge-like catalytic activity toward hydrogen evolution catalysis.Our work offers a facile and effective approach to modulate the catalytic surface of WS_(2) toward highly efficient HER catalysis.展开更多
Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,bu...Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:21875112,22109073Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20221321。
文摘Heteroatomic substitution and vacancy engineering of spinel oxides can theoretically optimize the oxygen evolution reaction(OER)through charge redistribution and d-band center modification but still remain a great challenge in both the preparation and catalytic mechanism.Herein,we proposed a novel and efficient Ar-plasma(P)-assisted strategy to construct heteroatom Mo-substituted and oxygen vacancies enriched hierarchical spinel Co_(3)O_(4)porous nanoneedle arrays in situ grown on carbon cloth(denoted P-Mo-Co_(3)O_(4)@CC)to improve the OER performance.Ar-plasma technology can efficiently generate vacancy sites at the surface of hydroxide,which induces the anchoring of Mo anion salts through electrostatic interaction,finally facilitating the substitution of Mo atoms and the formation of oxygen vacancies on the Co_(3)O_(4)surface.The P-Mo-Co_(3)O_(4)@CC affords a low overpotential of only 276 mV at 10 mA cm^(−2)for the OER,which is 58 mV superior to that of Mo-free Co_(3)O_(4)@CC and surpasses commercial RuO_(2)catalyst.The robust stability and satisfactory selectivity(nearly 100%Faradic efficiency)of P-Mo-Co_(3)O_(4)@CC for the OER are also demonstrated.Theoreti-cal studies demonstrate that Mo with variable valance states can efficiently regulates the atomic ratio of Co^(3+)/Co^(2+)and increases the number of oxygen vacancies,thereby inducing charge redistribution and tuning the d-band center of Co_(3)O_(4),which improve the adsorption energy of oxygen intermediates(e.g.,*OOH)on P-Mo-Co_(3)O_(4)@CC during OER.Furthermore,the two-electrode OER//HER electrolyzer equipped with P-Mo-Co_(3)O_(4)@CC as anode displays a low operation potential of 1.54 V to deliver a current density of 10 mA cm^(−2),and also exhibits good reversibility and anticurrent fluctuation ability under simulated real energy supply conditions,demonstrating the great potential of P-Mo-Co_(3)O_(4)@CC in water electrolysis.
基金financially supported by the National Natural Science Foundation of China (22109073, 22072067 and 21875112)the supports from National and Local Joint Engineering Research Center of Biomedical Functional Materialsa project sponsored by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Urea oxidation reaction (UOR),which has favorable thermodynamic energy barriers compared with oxygen evolution reaction (OER),can provide more cost-effective electrons for the renewable energy systems,but is trapped by its sluggish UOR kinetics and intricate reaction intermediates formation/desorption process.Herein,we report a novel and effective electrocatalyst consisting of carbon cloth supported nitrogen vacancies-enriched Ce-doped Ni_(3)N hierarchical nanosheets (Ce-Ni_(3)N @CC) to optimize the flat-footed UOR kinetics,especially the stiff rate-determine CO_(2)desorption step of UOR.Upon the introduction of valance state variable Ce,the resultant nitrogen vacancies enriched Ce-Ni_(3)N @CC exhibits an enhanced UOR performance where the operation voltage requires only 1.31 V to deliver the current density of 10 mA cm^(-2),which is superior to that of Ni_(3)N @CC catalyst (1.36 V) and other counterparts.Density functional theory (DFT) results demonstrate that the incorporation of Ce in Ni_(3)N lowers the formation energy of nitrogen vacancies,resulting in rich nitrogen vacancies in Ce-Ni_(3)N @CC.Moreover,the nitrogen vacancies together with Ce doping optimize the local charge distribution around Ni sites,and balance the adsorption energy of CO_(2)in the rate-determining step (RDS),as well as affect the initial adsorption structure of urea,leading to the superior UOR catalytic performance of Ce-Ni_(3)N @CC.When integrating the Ce-Ni_(3)N catalyst in UOR//HER and UOR//CO_(2)R flow electrolyzer,both of them perform well with low operation voltage and robust long-term stability,proofing that the thermodynamically favorable UOR can act as a suitable substitute anodic reaction compared with that of OER.Our findings here not only provide a novel UOR catalyst but also offer a promising design strategy for the future development of energy-related devices.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.22269015,U22A20107,22205119)Natural Science Foundation of Inner Mongolia Autonomous Region of China(Nos.2021ZD11,2019BS02015).
文摘Modulating surface charge redistribution based on interface and defect engineering has been considered as a resultful means to boost electrocatalytic activity.However,the mechanism of synergistic regulation of heterojunction and vacancy defects remains unclear.Herein,a Vs-CoP-CoS_(2)/C n-n heterojunction with sulfur vacancies is successfully constructed,which manifests superior electrocatalytic activity for oxygen evolution,as demonstrated by a low overpotential of 170 mV to reach 10 mA/cm^(2).The experimental results and density functional theory calculations testify that the outstanding OER performance of Vs-CoP-CoS_(2)/C heterojunction is owed to the synergistic effect of sulfur vacancies and built-in electric field at n-n heterogeneous interface,which accelerates the electron transfer,induces the charge redistribution,and regulates the adsorption energy of active intermediates during the reaction.This study affords a promising means to regulate the electrocatalytic performance by the construction of heterogeneous interfaces and defects,and in-depth explores the synergistic mechanisms of n-n heterojunction and vacancies.
基金This work is supported by the National Natural Science Foundation of China(No.52122702)Natural Science Foundation of Heilongjiang Province of China(No.JQ2021E005)Fundamental Research Foundation for Universities of Heilongjiang Province(No.LGYC2018JQ006).
文摘The basal planes of transition metal dichalcogenides are basically inert for catalysis due to the absence of adsorption and activation sites,which substantially limit their catalytic application.Herein,a facile strategy to activate the basal plane of WS_(2) for hydrogen evolution reaction(HER)catalysis by phosphorous-induced electron density modulation is demonstrated.The optimized P doped WS_(2)(P-WS_(2))nanowires arrays deliver a low overpotential of 88 mV at 10 mA·cm^(-2)with a Tafel slope of 62 mV·dec^(-1)for HER,which is substantially better than the pristine counterpart.X-ray photoelectron spectroscopy confirms the surface electron densities of WS_(2) have been availably manipulated by P doping.Moreover,density functional theory(DFT)studies further prove P doping can redistribute the density of states(DOS)around EF,which endow the inert basal plane of PWS_(2) with edge-like catalytic activity toward hydrogen evolution catalysis.Our work offers a facile and effective approach to modulate the catalytic surface of WS_(2) toward highly efficient HER catalysis.
基金National Natural Science Foundation of China,Grant/Award Number:22102079Taishan Scholar Program of Shandong Province,China,Grant/Award Number:tsqn202211162Natural Science Foundation of Shandong Province of China,Grant/Award Numbers:ZR2021YQ10,ZR2022QB163。
文摘Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.
基金financially supported by the National Natural Science Foundation of China (22005002)the Natural Science Foundation of Anhui Province (2208085Y03)+1 种基金Anhui University Scientific Research Start-up Fundsupported by the advanced computing resources provided by the Supercomputing Center of the University of Science and Technology of China。
