Tailoring Non‐Covalent Interaction Via Single Atom to Boost Interfacial Charge Transfer Toward Photoelectrochemical Water Oxidation

Abstract Photoelectrochemical (PEC) water splitting for hydrogen generation holds immense potential for addressing environmental and energy crises. Tailoring non‐covalent interaction via a single atom is anticipated to realize prominent hole extracting facilitating PEC performance, but it has never been reported. In this study, single atom Co‐N₄ is coordinated with 5‐fluoroanthranilic acid (FAA) molecules, then used as a non‐covalent hole‐extracting layer on a BiVO₄ substrate. Experiments including X‐ray absorption fine spectra, Kelvin probe force microscopy, transient absorption, and theoretical calculation demonstrate the FAA coordination alters the local configuration of the central Co atom, adjusting the interfacial non‐covalent interaction, thereby reducing the barrier of charge transfer between BiVO₄ and the hole‐extracting layer. Consequently, photogenerated carriers are more effectively separated, and the PEC water oxidation performance is significantly enhanced with the photocurrent density of 5.47 mA cm⁻² at 1.23 V versus RHE, much higher than those of previously reported BiVO₄ photoanodes composited with porphyrin‐based compounds. Experiments and theoretical simulation confirm that the boosted PEC performance originates from exceptional interfacial charge transfer rather than surface catalysis dynamic. This study provides an efficient strategy for tailoring non‐covalent interaction by regulating single‐atom coordination and promoting hole extract to boost PEC water oxidation activity.