镍掺杂Co4N纳米线束作为高效产氧电催化剂

Nickel-doped CoN nanowire bundles as efficient electrocatalysts for oxygen evolution reaction

发展储量丰富、高性价比的非贵金属产氧(OER)催化剂十分必要.具有金属特性的Co4N是极具潜力的候选催化剂之一,其性能受催化剂形貌和表面电子结构的影响.本文将镍掺杂到具有一维层级结构的Co4N纳米线束中,实现了对催化剂形貌和电子结构的有效调控.XPS结果表明,Ni掺杂可以提高Co3+的比例,而表面原位生成的羟基氧化物有利于OER反应进行.此外,该材料优良的导电性和一维层级结构有利于活性位点的充分暴露,使得材料的电催化性能显著提高.在1.0 mol L^(-1)KOH溶液中测试OER性能,Ni/Co摩尔比为0.25的催化剂表现最佳,只需233 mV的过电势就达到10 mA cm^(-2)电流密度,Tafel斜率仅为61 mV dec^(-1),且稳定性优异.本工作进而验证了Fe和Cu掺杂对Co4N催化剂OER性能的增强作用.

Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performance relying on specific nanostructures and electronic configurations.Herein,nickel was introduced as the dopant into one-dimensional (1D) hierarchical Co4N structures,achieving effective electronic regulation of Co4N toward high OER performance.The amount of Co3+increased after Ni-doping,and the in-situ formed surface oxyhydroxide during OER enhanced the electrocatalytic kinetics.Meanwhile,the 1D hierarchical structure further promoted the performances of Co4N owing to the high electrical conductivity and abundant activesites on the rough surface.As expected,the optimal Ni-doped Co4N with a Ni/Co molar ratio of 0.25 provides a small overpotential of 233 mV at a current density of 10 mA cm^(-2),with a low Tafel slope of 61 mV dec^(-1),and high long-term stability in 1.0 mol L^(-1)KOH.Following these results,the enhancement by doping the Co4N nanowire bundles with Fe and Cu was further evidenced for the OER.