The preparation of Ni/Mo-based ternary electrocatalysts by the self-propagating initiated nitridation reaction and their application for efficient hydrogen production

Abstract

In the hydrogen evolution reaction (HER), multi-component electrocatalysts with a synergistic effect may possess enhanced catalytic activity and broadened applicability in both acidic and alkaline media. Herein, we developed a novel strategy via the self-propagating initiated nitridation reaction for the synthesis of Mo₂C, MoNi₄, and Ni₂Mo₃N nanocrystals as active components assembled in a multiscale porous honeycomb-like carbon (Ni/MoCat@HCC). This strategy can be realized by simply calcining (NH₄)₆Mo₇O₂₄ and Ni(NO₃)₂ precursor hybrids under a H₂/Ar atmosphere at a fairly low temperature of 600 °C. It relies on the in situ thermal decomposition of (NH₄)₆Mo₇O₂₄ and the subsequent nitridation reaction with released NH₃, thus avoiding the continuous purging of NH₃ in the conventional method. The rich reaction intermediates during the calcination of bimetallic precursors also offer other catalytically active components that are controllable by varying the calcining procedure. Benefiting from the multiscale porous structure, ultrafine size of catalyst particles, and strong synergistic effect of several catalytically active components, the as-prepared Ni/MoCat@HCC exhibits extraordinary HER electrocatalytic activity with low onset overpotentials, small Tafel slopes, and excellent cycling stability in both acidic and alkaline media, outperforming most current noble-metal-free electrocatalysts. This study paves a novel way for synthesizing multi-component electrocatalysts with enhanced catalysis performance.