Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)i...Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is the premise to achieve both the zinc-air battery(ZAB)and overall water splitting.Herein,we utilize density functional theory to calculate the cobalt nitride(Co_(x)N,x=1,2,4,5.47)system,revealing that the Co_(5.47)N maybe exhibits a tri-functional activity due to the diverse valence states and high-density d-electron state of Co site.Furthermore,the electron of Co site is further delocalized by the electronic compensation effect of vanadium nitride(VN),thus improving the intermediates absorption and electrocatalytic activity.Accordingly,the Co_(5.47)N/VN heterojunction is designed and synthesized via an electrospinning and a subsequent pyrolysis route.As expected,it displays excellent HER,OER,and ORR activity in alkaline electrolyte,which can be applied to assemble ZAB with a high power density of 207mW/cm^(2)and overall water splitting system only requires a lower voltage of 1.53 V to achieve 10mA/cm^(2).The electron regulation effect of VN makes the Co valence state decrease in the reduction reaction whereas increase in the oxidization reaction as evidenced by quasi-operando XPS analyses.Importantly,two ZABs connected in series could drive overall water splitting,indicating the potential application in renewable energy technologies.展开更多
基金the National Key R&D Program of China(No.2023YFA1507204)the National Natural Science Foundation of China(Nos.U20A20250,22279030,22179034)the Natural Science Foundation of Heilongjiang Province(No.ZD2023B002).
文摘Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is the premise to achieve both the zinc-air battery(ZAB)and overall water splitting.Herein,we utilize density functional theory to calculate the cobalt nitride(Co_(x)N,x=1,2,4,5.47)system,revealing that the Co_(5.47)N maybe exhibits a tri-functional activity due to the diverse valence states and high-density d-electron state of Co site.Furthermore,the electron of Co site is further delocalized by the electronic compensation effect of vanadium nitride(VN),thus improving the intermediates absorption and electrocatalytic activity.Accordingly,the Co_(5.47)N/VN heterojunction is designed and synthesized via an electrospinning and a subsequent pyrolysis route.As expected,it displays excellent HER,OER,and ORR activity in alkaline electrolyte,which can be applied to assemble ZAB with a high power density of 207mW/cm^(2)and overall water splitting system only requires a lower voltage of 1.53 V to achieve 10mA/cm^(2).The electron regulation effect of VN makes the Co valence state decrease in the reduction reaction whereas increase in the oxidization reaction as evidenced by quasi-operando XPS analyses.Importantly,two ZABs connected in series could drive overall water splitting,indicating the potential application in renewable energy technologies.
