Elucidating the inherent origins of the sluggish hydrogen evolution reaction(HER)kinetics in alkaline media and developing high-performance electrocatalysts are fundamental for the advances of conventional alkaline wa...Elucidating the inherent origins of the sluggish hydrogen evolution reaction(HER)kinetics in alkaline media and developing high-performance electrocatalysts are fundamental for the advances of conventional alkaline water electrolyzers and emerging anion exchange membrane(AEM)electrolyzers.Here we present a facile electrochemical modification strategy for the synthesis of bi-component Co–Mo_((18%))/A-Co(OH)_(2)catalyst toward efficient HER catalysis in alkaline media.Porous Co–Mo alloys with adjustable Mo/Co atomic ratio are first prepared by H2-assisted cathodic electrodeposition.By virtue of the appropriate electronic structure and hydrogen binding energy,Co–Mo_((18%))is the most HER active among the alloys and is further activated by a constant-current electrochemical modification process.Physical characterizations reveal the formation of amorphous Co(OH)_(2)nanoparticles on the surface.Electrokinetic analysis combined with theoretical calculations reveal that the in-situ formed Co(OH)_(2)can efficiently promote the water dissociation,resulting in accelerated Volmer-step kinetics.As a result,the Co–Mo_((18%))/A-Co(OH)_(2)simultaneously achieves the optimization of the two factors dominating alkaline HER activity,i.e.,water dissociation and hydrogen adsorption/desorption via the bifunctional synergy of the bi-components.The high HER activity(η10 of 47 mV at 10 mA cm^(-2))of Co–Mo_((18%))/A-Co(OH)_(2)is close to benchmark Pt/C catalyst and comparable or superior to the most active non-noble metal catalysts.展开更多
The intrinsic activity of Co(OH)_(2) for oxygen evolution reaction(OER)may be elaborately improved through the suitable valence adjustment.Ce modification at electronic level is proved to be an efficient strategy owin...The intrinsic activity of Co(OH)_(2) for oxygen evolution reaction(OER)may be elaborately improved through the suitable valence adjustment.Ce modification at electronic level is proved to be an efficient strategy owing to the flexible transformation of Ce^(3+)/Ce4+.Herein,Ce0.21@Co(OH)_(2) with the optimized Ce doping have been fabricated to tailor the fast electron transfer for the enhanced activity and stability for OER.Firstly,the obtained core-shell structure composed of vertical loose Co(OH)_(2) sheets not only exposes a large number of active sites,but also provides channels for Ce doping.Secondly,the high pressure microwave with instantaneous heating can fast introduce Ce into Co(OH)_(2),obtaining Cex@Co(OH)_(2) with well dispersion and close integration.The intimated interaction between Ce and Co species may provide the"d-f electronic ladders"for accelerating electron transfer of the catalytic surface.Meanwhile,Ce promotes the formation of Co-superoxide intermediate and/or the release of oxygen,which is considered to be the rate-determining step for OER.The electrochemical measurements confirmed the low overpotential of 300 m V at 10 m A cm^(-2) and great stability of Ce0.21@Co(OH)_(2) for OER.This work demonstrates a meaningful approach to realize the tuned electronic structure through metal doping.展开更多
基金supported by the National Natural Science Foundation of China(No.51771037)Low Carbon Energy Research Funding Initiative(No.SC22/22-71151E).
文摘Elucidating the inherent origins of the sluggish hydrogen evolution reaction(HER)kinetics in alkaline media and developing high-performance electrocatalysts are fundamental for the advances of conventional alkaline water electrolyzers and emerging anion exchange membrane(AEM)electrolyzers.Here we present a facile electrochemical modification strategy for the synthesis of bi-component Co–Mo_((18%))/A-Co(OH)_(2)catalyst toward efficient HER catalysis in alkaline media.Porous Co–Mo alloys with adjustable Mo/Co atomic ratio are first prepared by H2-assisted cathodic electrodeposition.By virtue of the appropriate electronic structure and hydrogen binding energy,Co–Mo_((18%))is the most HER active among the alloys and is further activated by a constant-current electrochemical modification process.Physical characterizations reveal the formation of amorphous Co(OH)_(2)nanoparticles on the surface.Electrokinetic analysis combined with theoretical calculations reveal that the in-situ formed Co(OH)_(2)can efficiently promote the water dissociation,resulting in accelerated Volmer-step kinetics.As a result,the Co–Mo_((18%))/A-Co(OH)_(2)simultaneously achieves the optimization of the two factors dominating alkaline HER activity,i.e.,water dissociation and hydrogen adsorption/desorption via the bifunctional synergy of the bi-components.The high HER activity(η10 of 47 mV at 10 mA cm^(-2))of Co–Mo_((18%))/A-Co(OH)_(2)is close to benchmark Pt/C catalyst and comparable or superior to the most active non-noble metal catalysts.
基金financially supported by the National Natural Science Foundation of China(21776314)the Qingdao Science and Technology Benefiting People Special Project(20-3-4-8-nsh)+2 种基金the Fundamental Research Funds for the Central Universities(20CX02212A)the Development Fund of State Key Laboratory of Heavy Oil Processingthe Postgraduate Innovation Project of China University of Petroleum(YCX2020046)。
文摘The intrinsic activity of Co(OH)_(2) for oxygen evolution reaction(OER)may be elaborately improved through the suitable valence adjustment.Ce modification at electronic level is proved to be an efficient strategy owing to the flexible transformation of Ce^(3+)/Ce4+.Herein,Ce0.21@Co(OH)_(2) with the optimized Ce doping have been fabricated to tailor the fast electron transfer for the enhanced activity and stability for OER.Firstly,the obtained core-shell structure composed of vertical loose Co(OH)_(2) sheets not only exposes a large number of active sites,but also provides channels for Ce doping.Secondly,the high pressure microwave with instantaneous heating can fast introduce Ce into Co(OH)_(2),obtaining Cex@Co(OH)_(2) with well dispersion and close integration.The intimated interaction between Ce and Co species may provide the"d-f electronic ladders"for accelerating electron transfer of the catalytic surface.Meanwhile,Ce promotes the formation of Co-superoxide intermediate and/or the release of oxygen,which is considered to be the rate-determining step for OER.The electrochemical measurements confirmed the low overpotential of 300 m V at 10 m A cm^(-2) and great stability of Ce0.21@Co(OH)_(2) for OER.This work demonstrates a meaningful approach to realize the tuned electronic structure through metal doping.
