Kinetics‐Boosted Bimetallic Organic Complexes Modified BiVO ₄ Photoanodes for Photoelectrochemical Water Oxidation

Metal–organic complexes (MOCs) have been widely studied as efficient oxygen evolution catalysts (OECs) owing to their catalytic active sites with tunable electronic structure. MOCs comprised of metallic cations and poly‐carboxyl ligands, such as terephthalic acid, are widely studied for OEC loading. However, MOCs containing organic ligands with mono‐carboxyl groups are rarely studied as cocatalysts for PEC water oxidation. In this study, three types of organic ligands with different carboxyl numbers, including benzoic acid (BEN), p‐phthalic acid (PTA), and 1,3,5‐benzenetricarboxylic acid (BTC), were selected for MOCs assembly. The impact of these MOCs modified BiVO ₄ photoanodes on PEC performance was examined. Binary Fe and Ni cations as coordination centers were demonstrated to have a synergistic effect on PEC water oxidation. The optimized FeNi bimetallic‐BEN‐based MOCs modified BiVO ₄ photoanode exhibited the highest PEC performance with a photocurrent density more than 6 times that of bare BiVO ₄ and the BiVO ₄ /FeNi‐MOC1 photoanode using the mono‐carboxyl BEN ligand exhibits excellent stability. This study provides a new insight into designing a bimetallic organic complex with a monocarboxyl ligand as a cocatalyst on BiVO ₄ electrode for its PEC performance improvement.