Electrodeposited Ternary CuNiMo Catalysts for Alkaline Hydrogen Oxidation

In this study, we investigated ternary transition metal catalysts composed of Cu, Ni, and Mo for application to hydrogen oxidation reaction (HOR) in alkaline electrolyte. A series of catalysts with a wide range of elemental compositions were fabricated by a simple electrodeposition method, and their material and electrochemical properties were investigated. In particular, to avoid inaccurate activity measurements due to oxidation and reduction of the transition metal-based catalysts during the HOR test, the electrochemical measurements were performed in both H₂- and N₂-saturated electrolytes, and the results were compared. The fabricated CuNiMo catalyst with an optimized composition exhibited an excellent HOR activity of 2.03 mA cm⁻² at 0.1 V_RHE, while the current density decreased only by 0.55 mA cm⁻² after 3000 cycles. The enhanced HOR activity is attributed to the combined effects of the modified crystal structure, increased surface area, alloying effects beneficial to the hydrogen binding energy and OH⁻ binding energy, and appropriate surface compositions between the H-adsorbing metallic state and OH-adsorbing oxophilic states. The characteristics of the catalyst demonstrated in this study can provide insights for the development of non-precious catalysts for HOR in alkaline electrolytes.

Graphical Abstract