Optimizing molybdenum-cobalt (Mo-Co) ratio in phosphorus enriched CoMoP nanorods for enhanced hydrogen evolution performance

Tunable electronic structure and unique physicochemical properties have made transition metal phosphides (TMP) promising electrocatalysts for hydrogen evolution reaction (HER). However, limited stability under electrocatalytic conditions leads to rapid degradation of electrocatalytic performance. Therefore, constructing high performance phosphide catalysts enabling stable electro-catalysis, especially under alkaline conditions, is still challenging and in great urgency. In this study, cobalt-molybdenum-based phosphides (CoMoP) were rationally designed and synthesized through a two-step approach based on hydrothermal treatment and subsequent gas–solid reaction for the alkaline HER. This method enables the incorporation of mixed-valent states of Mo and the formation of nanorod-shaped porous structure, creating catalysts with enhanced active sites, low hydrolysis energy barrier, and optimized electronic properties. Due to the combined effect of these characteristics, the as-prepared CoMoP exhibit excellent electrocatalytic performance in HER, including excellent catalytic activity and high stability. Typically, the optimized sample CoMoP-2 (with Mo-Co feeding ratio of 1:2) provided a quite low overpotential of 89 mV for achieving 10 mA cm −2 , and good catalytic stability with no decent degradation in catalytic performance after 48 h continuous electrolysis. This study offers a facile and low-cost strategy for developing non-noble bimetallic electrocatalysts for effective and sustainable hydrogen evolution.