ZIF-67-templated NiCoP bimetallic catalysts for enhanced water splitting performance

Abstract

Efficient electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are essential to overcoming the slow kinetics of water electrolysis. In this study, a bimetallic NiCoP catalyst with a distinctive hollow structure was synthesized via a ZIF-67 template, followed by etching with Ni²⁺ aqueous solution and a subsequent phosphorization process. The resulting material demonstrates exceptional electrochemical performance. In HER, it exhibits excellent catalytic activity, achieving an overpotential of 134.6 mV at a current density of 10 mA cm⁻² and a Tafel slope of 72.3 mV·dec⁻¹. For OER, at a current density of 10 mA cm⁻², the overpotential is 273 mV, with a Tafel slope of 88.9 mV·dec⁻¹. Moreover, the catalyst shows excellent long-term stability. Density functional theory (DFT) calculations indicate that the incorporation of Ni into CoP alters the electronic states at the Fermi level, thereby improving its electrical conductivity. This work not only offers novel insights into the structural design of water splitting catalysts but also highlights the promising potential of NiCoP as an efficient catalyst in the energy conversion domain.