Enhancing The Hydrogen Evolution Performance Of Nickel By The Control Of Surface And Interface

Energy and environmental issues have been the focus of attention in recent years,and all countries in the world are committed to the development and utilization of new energy.Hydrogen energy is considered as the most promising energy carrier in the future because of its high energy density,pollution-free and renewable advantages.Electrolytic water hydrogen production is widely favored due to its high purity and relatively mature technology.However,the industrial hydrogen production voltage?1.8-2V?is much higher than the theoretical hydrogen production voltage?1.23V?,causing a great energy loss,which mainly comes from overpotential of cathode and anode catalysts.It is well known that noble metal Pt and its compounds are good catalysts for hydrogen evolution,but their high cost limits their application.Therefore,the development of non-noble metal hydrogen evolution catalysts with high efficiency,low cost and good stability is of great significance for electrolytic water hydrogen production industry.The transition metal/metal oxide?metal hydroxide?heterojunction catalysts have comparable catalytic activity to Pt.The metal has suitable hydrogen adsorption free energy.The metal oxide?hydroxid?can promote the decomposition of water and the desorption of intermediate products.Combining the two catalysts,an efficient catalyst for hydrogen evolution reaction can be obtained.However,there is still a lack of research on the interface control of metal/metal oxide?hydroxide?heterojunction catalysts,and in the long-term test of metal/metal oxide catalysts,oxides will be reduced to metals,resulting in catalyst deactivation.In order to solve the above problems,This paper aimed to prepare highly efficient and stable non-noble metal hydrogen evolution catalysts,on the basis of electrodeposited nickel nanosheets,wormlike Ni/NiO hydrogen evolution catalysts were obtained through three different oxidation control methods,they have excellent catalytic activity in alkali solution.NiO is dispersed on the nickel nanosheets,which increases the interface between the metal and the oxide,and provides more active sites.Moreover,this structure can completely expose the interface to the electrolyte,which is conducive to full contact between the interface and the electrolyte and promotes charge transfer.After that,in order to increase the stability of the worm-like Ni/NiO,Fe was doped on worm-like Ni/NiO surface by surface oxide doping,and a highly efficient and stable hydrogen evolution catalyst was obtained.The doping of Fe slows down the reduction rate of NiO,thus greatly increases the stability.The prepared Ni/Ni_xFe_1-xO samples were characterized by detailed electrochemistry and histological structure.When the current density was 10mA/cm²,the hydrogen evolution overpotential was 68mV.The overpotential is only increased by 9mV after 10 mA/cm²constant current test for 10 h.Its performance is better than most non-noble metal-based planar catalytic electrodes reported at home and abroad.Ni/NiO activity decay is mainly caused by reduction of NiO,so doping metal with more negative reduction potential in NiO can prevent the reduction or slow down the reduction rate.