Tuning the electrocatalytic perfomance of mixed transition-metal hydroxides for hydrogen production

Water electrolysis is considered a key technology to meet global energy demands by sustainably producing green hydrogen and oxygen fuel. Although much progress has been made to improve the effectiveness of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), the cathodic and anodic reactions respectively, the performance of electrochemical cells is still constrained by the lack of dual-selectivity and degradation of the catalytic components. Here, we investigate the performance and mechanism of multimetal catalysts serving dual functionality in both OER and HER of water electrolysis under electrochemical conditions. Using density functional theory to gain insight as the active site and mechanism, we propose that the inclusion of a minor amount of Cr increases the degeneracy of energetic states that lowers the cost of forming the O 2 p–d bond and H 1 s–d bond due to the hybridization of s, p, and d orbitals from Cr compared to Ti, V, and Mn. The implicit self-consistent continuum solvation (SCCS) model is employed to model the activity of the multimetal catalysts under an applied voltage in both alkaline and acidic conditions. This study demonstrates how tuning the amount of dopants in the nanocrystalline Fe, Co, and Ni structure is important for improving bifunctional catalytic behavior in water electrolysis.