Defects engineering is an efficient strategy to enhance the performance of electrode materials by modulating the local electronic structure but usually requires costly and complicated processing.Here,an electrochemica...Defects engineering is an efficient strategy to enhance the performance of electrode materials by modulating the local electronic structure but usually requires costly and complicated processing.Here,an electrochemical reduction etching method has been developed for controllable tailoring of the cationic defects in iron-based oxides under mild conditions.The optimized defective spinel-type iron nickel oxide exhibits an overpotential as low as 270 mV at 10 mA cm−2 and a Tafel slope of only 33.8 mV dec−1 for the oxygen evolution reaction(OER),outperforming the benchmark RuO2 and pristine oxide.Experiments and theoretical calculations reveal that Fe vacancies can enhance Ni–O covalency,increase the density of active sites,and optimize the surface electronic structure,which promote the water adsorption/activation and moderate oxygen intermediate species adsorption,thus significantly enhancing OER activity.This work provides a promising approach to create cation deficiency and mechanistic insight to understand the vacancy-induced enhancement of oxygen electrocatalysis.展开更多
The facile synthesis of highly active and stable bifunctional electrocatalysts to catalyze water splitting is attractive but challenging.Herein,we report the electrodeposition of Pt-decorated Ni(OH)_(2)/CeO_(2)(PNC)hy...The facile synthesis of highly active and stable bifunctional electrocatalysts to catalyze water splitting is attractive but challenging.Herein,we report the electrodeposition of Pt-decorated Ni(OH)_(2)/CeO_(2)(PNC)hybrid as an efficient and robust bifunctional electrocatalyst.The graphite-supported PNC catalyst delivers superior hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities over the benchmark Pt/C and RuO_(2),respectively.For overall water electrolysis,the PNC hybrid only requires a cell voltage of 1.45V at 10mAcm-2 and sustains over 85 h at 1000mAcm^(-2).The remarkable HER/OER performances are attributed to the superhydrophilicity and multiple effects of PNC,in which Ni(OH)_(2)and CeO_(2)accelerate HER on Pt due to promoted water dissociation and strong electronic interaction,while the electron-pulling Ce cations facilitate the generation of high-valence Ni OER-active species.These results suggest the promising application of PNC for H2 production from water electrolysis.展开更多
Metallic zinc is attractive anode material of rechargeable aqueous Zn-based batteries due to its ambient stability,high volumetric capacity,and abundant reserves.Nonetheless,Zn anodes suffer from issues such as low co...Metallic zinc is attractive anode material of rechargeable aqueous Zn-based batteries due to its ambient stability,high volumetric capacity,and abundant reserves.Nonetheless,Zn anodes suffer from issues such as low coulombic efficiency(CE),large polarization and dendrite formation.Herein,uniform Zn electrodeposition is reported on carbon substrates by selective nitrogen doping.Combined experimental and theoretical investigations demonstrate that pyrrolic and pyridinic nitrogen doped in carbon play beneficial effect as zinc-philic sites to direct nucleation and growth of metallic Zn,while negligible effect is observed for graphite nitrogen in Zn plating.The carbon cloth with modified amount of doped pyrrolic and pyridinic nitrogen stabilizes Zn plating/stripping with 99.3%CE after 300 cycles and significantly increases the deliverable capacity at high depth of charge and discharge compared to undoped carbon substrate and Zn foil.This work provides a better understanding of heteroatom doping effect in design and preparation of stable 3 D carbon-supported zinc anode.展开更多
基金supported by MOST(2017YFA0206700 and 2018YFB1502100)NSFC(21871149,21925503,and 51571125)+2 种基金MOE(B12015)Tianjin Project(18JCZDJC31100)the Fundamental Research Funds for the Central Universities.
文摘Defects engineering is an efficient strategy to enhance the performance of electrode materials by modulating the local electronic structure but usually requires costly and complicated processing.Here,an electrochemical reduction etching method has been developed for controllable tailoring of the cationic defects in iron-based oxides under mild conditions.The optimized defective spinel-type iron nickel oxide exhibits an overpotential as low as 270 mV at 10 mA cm−2 and a Tafel slope of only 33.8 mV dec−1 for the oxygen evolution reaction(OER),outperforming the benchmark RuO2 and pristine oxide.Experiments and theoretical calculations reveal that Fe vacancies can enhance Ni–O covalency,increase the density of active sites,and optimize the surface electronic structure,which promote the water adsorption/activation and moderate oxygen intermediate species adsorption,thus significantly enhancing OER activity.This work provides a promising approach to create cation deficiency and mechanistic insight to understand the vacancy-induced enhancement of oxygen electrocatalysis.
基金This work was supported by the National Natural Science Foundation of China(21871149,52001171,and 51571125)the Ministry of Science and Technology(2018YFB1502100)+3 种基金the Tianjin Project(18JCZDJC31100)the Ministry of Education(B12015)the NCC Fund(NCC2020FH03)the Fundamental Research Funds for the Central Universities.
文摘The facile synthesis of highly active and stable bifunctional electrocatalysts to catalyze water splitting is attractive but challenging.Herein,we report the electrodeposition of Pt-decorated Ni(OH)_(2)/CeO_(2)(PNC)hybrid as an efficient and robust bifunctional electrocatalyst.The graphite-supported PNC catalyst delivers superior hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities over the benchmark Pt/C and RuO_(2),respectively.For overall water electrolysis,the PNC hybrid only requires a cell voltage of 1.45V at 10mAcm-2 and sustains over 85 h at 1000mAcm^(-2).The remarkable HER/OER performances are attributed to the superhydrophilicity and multiple effects of PNC,in which Ni(OH)_(2)and CeO_(2)accelerate HER on Pt due to promoted water dissociation and strong electronic interaction,while the electron-pulling Ce cations facilitate the generation of high-valence Ni OER-active species.These results suggest the promising application of PNC for H2 production from water electrolysis.
基金supported by Tianjin Project(No.18JCZDJC31100)Ministry of Science and Technology(No.2017YFA0206702)+2 种基金National Natural Science Foundation of China,(Nos.21871149 and 21925503)Ministry of Education(No.B12015)the Fundamental Research Funds for the Central Universities(No.63201035)。
文摘Metallic zinc is attractive anode material of rechargeable aqueous Zn-based batteries due to its ambient stability,high volumetric capacity,and abundant reserves.Nonetheless,Zn anodes suffer from issues such as low coulombic efficiency(CE),large polarization and dendrite formation.Herein,uniform Zn electrodeposition is reported on carbon substrates by selective nitrogen doping.Combined experimental and theoretical investigations demonstrate that pyrrolic and pyridinic nitrogen doped in carbon play beneficial effect as zinc-philic sites to direct nucleation and growth of metallic Zn,while negligible effect is observed for graphite nitrogen in Zn plating.The carbon cloth with modified amount of doped pyrrolic and pyridinic nitrogen stabilizes Zn plating/stripping with 99.3%CE after 300 cycles and significantly increases the deliverable capacity at high depth of charge and discharge compared to undoped carbon substrate and Zn foil.This work provides a better understanding of heteroatom doping effect in design and preparation of stable 3 D carbon-supported zinc anode.
