脱合金化制备纳米多孔Ni-Fe合金及其电催化性能

采用真空熔炼与固溶相结合的方法获得原子分数为Ni_30-xFe_xMn₇₀(x=0,10,20)的前驱体合金,通过脱合金化方法制备纳米多孔Ni及Ni-Fe合金,采用X射线衍射(XRD)、扫描电子显微镜(SEM)分析合金相组成和微观结构,运用线性扫描伏安法、交流阻抗、方波电位法及计时电位法研究电极的析氢电催化性能。结果表明:加入Fe获得了片状结构的纳米多孔Ni-Fe合金,提高了纳米多孔Ni的表面积,且Fe与Ni产生协同效应,能够有效提高合金的析氢电催化活性。当Fe含量为10%(原子分数)时,脱合金化得到的纳米多孔Ni-Fe合金表面积最大,析氢电催化性能最好,在0.1A/cm^2电流密度下,析氢过电位仅56mV,经10h连续电解,表现出良好的电催化活性和电化学稳定性。

Preparation and electrocatalytic performance of nanoporous Ni-Fe alloy by dealloying

The precursor alloy with atomic fraction is Ni 30-xFexMn70(x=0,10,20)by means of vacuum melting and solid solution,using the method of dealloying to nanoporous Ni and Ni-Fe alloy,with XRD,SEM phase compositions and microstructure were analyzed.The electrocatalytic performance for hydrogen evolution reaction was investigated by linear sweep voltammetry(LSV),electrochemical impedance spectroscopy(IMP),square wave potential technique(SWPT)and chrono potentiometry(CP).The results show that the nanoporous Ni-Fe alloy with lamellar structure is obtained by adding Fe,which improves the surface area of nanoporous Ni,and synergistic effect between Fe and Ni is produced,which can effectively improve the electrocatalytic activity of hydrogen evolution of the alloy.When the atom fraction of Fe is 10%,the surface area of nanoporous Ni-Fe alloy obtained by dealloying is the largest,and the electrocatalytic performance of hydrogen evolution is the best.Under the current density of 0.1A/cm^2,hydrogen evolution overpotential is only 56mV,after continuous electrolysis for 10h,the alloy exhibits the high electrocatalytic activity and good electrochemical stability.