Nickel-doped Co4N nanowire bundles as efficient electrocatalysts for oxygen evolution reaction

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 active-sites 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 mAcm(-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.

Automated summary

In this study, nickel doping was introduced into one-dimensional hierarchical Co4N structures to enhance OER performance, resulting in increased amount of Co3+ and improved electrocatalytic kinetics. The optimal Ni-doped Co4N with Ni/Co molar ratio of 0.25 exhibited excellent OER performance, with low overpotential and Tafel slope, as well as high long-term stability. Doping with Fe and Cu further enhanced the OER activity of Co4N nanowire bundles.