3D nanoporous NiCoP as a highly efficient electrocatalyst for the hydrogen evolution reaction in alkaline electrolyte

Abstract

Transition metal phosphides (TMPs) have demonstrated great potential for accelerating the electrocatalytic hydrogen evolution reaction (HER). Herein, we present the facile synthesis of the nickel cobalt phosphide (NiCoP) electrocatalyst with a 3D nanoporous structure formed by dealloying and combined low temperature chemical vapor deposition (CVD) phosphorization. Its activity is attributed to the large specific surface area of the dealloyed substrate and the good intrinsic activity of the bimetallic phosphides. The as-prepared NiCoP is found to exhibit a low hydrogen evolution reaction overpotential of 130 mV (η₁₀) and a small Tafel slope of 93 mV dec⁻¹ in an alkaline medium. Moreover, no significant deactivation is observed even after running for at least 2000 CV cycles, suggesting excellent stability. The bimetallic phosphide also shows superior HER activity compared with single-metal phosphides, such as cobalt phosphide and nickel phosphide. It is expected that our work could provide a new idea for the design of highly active non-noble-metal materials for the electrocatalytic HER.