Electrocatalysts with Highly Dispersed Cerium in Nickel Matrix for Hydrogen Evolution in Alkaline Electrolyte

Abstract It is challenging to develop highly active and durable electrocatalysts for hydrogen evolution reaction (HER) in alkaline water electrolysis. Herein, an electrocatalyst is synthesized with highly dispersed cerium in a nickel matrix, showing an overpotential of 169 mV for HER at a current density of 500 mA cm⁻², about 137 mV lower than that observed without cerium. Kinetic analysis results suggest that doping cerium facilitates the evolution of intermediate H for HER, thus accelerating the process of water dissociation. Density functional theory (DFT) calculations also indicate that the introduction of highly dispersed cerium can lower the energy barrier of the kinetically sluggish Volmer step by altering the orbital occupation near the Fermi level, promoting the process of water dissociation. Furthermore, the electrolyzer constructed with the electrocatalyst exhibits a cell voltage as low as 1.67 V at 800 mA cm⁻² for 2000 h in 7 м KOH at 80 °C. The robust property makes it an excellent candidate electrocatalyst for practical applications.