Theory-guided design of 3d transition-metal doped Ni2P(001) enables superior bifunctional catalysis for hydrazine-assisted hydrogen production

We systematically investigate the doping of 24 homonuclear 3 d transition metal configurations into the Ni 2 P(001). Our results reveal that the 1*Cr@Ni 2 P, 1*V@Ni 2 P, and 2*Ti@Ni 2 P are candidates for bifunctional hydrazine oxidation reaction (HzOR)/hydrogen evolution reaction (HER) electrocatalysis because they exhibit low formation energies and display more favorable Gibbs free energy barriers of the rate-determining steps (Δ G RDS ) and optimal hydrogen adsorption Gibbs free energies (Δ G H* ) compared to pure Ni 2 P(001). Our machine learning analyses indicate that the formation energy and the d -band center serve as key predictive descriptors for HzOR and HER activities, respectively. Moreover, constant-potential density functional theory calculations confirm that at pH = 7 and U = 0 V vs reversible hydrogen electrode, the 1*Cr@Ni 2 P, 1*V@Ni 2 P, and 2*Ti@Ni 2 P electrocatalysts exhibit excellent bifunctional activity, with Δ G RDS /Δ G H* values of 0.10/−0.37 eV, 0.22/−0.19 eV, and 0.20/−0.10 eV, respectively. Thus, this can significantly reduce practical implementation costs compared to harsh acidic or alkaline environments.