Co-deposition of Ni-Mo alloy film catalysts for hydrogen evolution from an ethylene glycol system

Owing to the depletion of renewable energy sources, manufacturing stable, efficient and economical non-noble electrode materials for the hydrogen evolution reaction (HER) through electrochemical water splitting is a promising avenue. In this work, Ni-Mo alloy films containing different Mo concentrations were synthesized via potentiostatic technique, and the mechanism of Ni2+ and Mo6+ co-deposition in an ethylene glycol system (EG) was recorded. The co-deposition mechanism of Mo6+ and Ni2+ in the EG shows that the existence of Ni2+ can facilitate the reduction of Mo6+, while Mo6+ can impede the reduction of Ni2+. Furthermore, both functions could be reinforced owing to the improved content of Ni2+ and Mo6+ in the EG system. Ni-Mo alloy films containing different Mo concentrations could be obtained from the EG solution, and their microstructures could be changed by changing the Mo content. Scanning electron microscopy micrographs exhibit that Ni-Mo alloy films with 10.84 wt% Mo show a cauliflower-like pattern. Benefiting from the alloying technique to modify the Ni electronic structure with Mo, coupled with the concurrent presence of an appropriate cauliflower-like structure, Ni-Mo alloy films with 10.84 wt% Mo show remarkable catalytic activity and durability with an HER overpotential of 74 mV (eta 10, overpotential was recorded at j = 10 mA cm-2) in 1.0 M KOH solution.