Component design of Ni-based rock-salt structure oxygen evolution reaction catalyst via cluster plus glue atom model

The development of efficient and durable oxygen evolution reaction (OER) electrocatalysts is crucial for advancing alkaline water electrolysis and enabling sustainable hydrogen production. Nickel-based oxides with rock-salt structures are particularly promising owing to their earth abundance and favorable redox properties. However, strong Ni–Ni d–d electronic interactions in NiO frequently result in excessive *O adsorption, sluggish kinetics, and structural instability under OER conditions. Herein, we employ the cluster-plus-glue-atom model to rationally design Ni–Mg rock-salt oxides, with a focus on how Mg substitution at glue-atom sites modulates the electronic structure of the central Ni active site. The resulting Ni#Mg5 catalyst requires an overpotential of only 247 mV to deliver a current density of 10 mA·cm–2 and maintains stable performance over 140 h. Density functional theory (DFT) calculations reveal that Mg atoms at glue-atom sites introduce a distinctive Mg 2s orbital shielding effect. This effect weakens Ni–Ni d–d coupling, optimizes Ni 3d–O 2p hybridization, elevates the Ni 3d band center, and reduces the formation energy barrier of the *OH intermediate. This work establishes orbital shielding as a key electronic modulation strategy and highlights the predictive power of the cluster-plus-glue-atom model for the rational design of high-performance Ni-based OER electrocatalysts.