Synergistic Interfacial and Doping Engineering of Heterostructured NiCo(OH)x-CoyW as an Efficient Alkaline Hydrogen Evolution Electrocatalyst

Highlights A promising solar-powered environmentally friendly process for the synthesis and application of catalysts for hydrogen evolution reaction has been proposed. A delicate NiCo(OH) x -Co y W catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition, followed by electrochemical etching process. The excellent catalytic effect of NiCo(OH) x -Co y W for the hydrogen evolution reaction was systematically investigated through various physical and electrochemical analyses. To achieve high efficiency of water electrolysis to produce hydrogen (H 2 ), developing non-noble metal-based catalysts with considerable performance have been considered as a crucial strategy, which is correlated with both the interphase properties and multi-metal synergistic effects. Herein, as a proof of concept, a delicate NiCo(OH) x -Co y W catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition, followed by an electrochemical etching-growth process, which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction, with an overpotential of 21 and 139 mV at 10 and 500 mA cm −2 , respectively. Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH) x /Co y W heterogeneous interface resulted in favorable electron redistribution and faster electron transfer efficiency. The amorphous NiCo(OH) x strengthened the water dissociation step, and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H 2 desorption. In addition, NiCo(OH) x -Co y W exhibited desirable urea oxidation reaction activity for matching H 2 generation with a low voltage of 1.51 V at 50 mA cm −2 . More importantly, the synthesis and testing of the NiCo(OH) x -Co y W catalyst in this study were all solar-powered, suggesting a promising environmentally friendly process for practical applications.