Orbital‐Selective Modulation of Spatial p z ‐s Hybridization for Enhanced Photocatalytic H 2 Evolution: Insights From NiSe@ReS 2+ x Cocatalyst

ABSTRACT Regulating the p orbital structure of nonmetal active sites is a potential strategy to optimize hydrogen adsorption. However, existing modification ideas primarily focus on the total energy of the p orbitals, while overlooking the crucial spatial information of the multiple projected p x , p y , and p z orbitals, causing a random and nondirectional orbital modification. Herein, we propose a spatial orbital‐selective modulation engineering to realize precise and efficient optimization of H adsorption on a core‐shell NiSe@ReS 2+ x cocatalyst. Theoretical calculations find that the H adsorption intrinsically originates from the selective hybridization between individual S p z and H 1 s orbitals ( p z ‐s ), which unlocks a most direct approach to optimize H adsorption. Based on this, we demonstrate that H adsorption on S sites is directionally weakened by selectively charging spatial S p z from NiSe to produce electron‐rich p z δ− orbitals. This process increases the projected antibonding‐orbital occupancy, weakens the spatial p z ‐s hybridization, and lowers the H 2 ‐formation energy barrier of ReS 2+ x , ultimately achieving an improved H 2 ‐evolution activity. This work offers spatial orbital‐level insights into precisely designing effective catalysts for artificial photosynthesis.