Electron–Hole Dual Cocatalyst Promoted ZnIn ₂ S ₄ for Photocatalytic H ₂ Evolution Coupled With B

ABSTRACT

The central challenge in photocatalysis is to direct photogenerated electrons and holes toward the simultaneous and efficient production of hydrogen and value‐added chemicals. To address the pronounced charge recombination and sluggish surface kinetics of ZnIn ₂ S ₄ nanoflowers, we construct a ternary photocatalyst synergistically decorated with dual cocatalysts (Ni ₂ P and PdS), enabling visible‐light‐driven H ₂ evolution coupled with the selective oxidation of benzyl alcohol to benzaldehyde. In this architecture, ZnIn ₂ S ₄ serves as the light‐harvesting and charge‐generation center. Benefiting from its quasi‐metallic conductivity, Ni ₂ P acts as an electron cocatalyst to accelerate proton reduction, whereas PdS functions as a hole cocatalyst to facilitate hole extraction, migration, and consumption. The spatial separation of reduction and oxidation sites enables directional charge separation and efficient utilization, delivering an H ₂ evolution rate of 15.07 mmol g ⁻¹  h ⁻¹ and a benzyl alcohol conversion of 87.61%. Femtosecond transient absorption spectroscopy (fs‐TAS), Kelvin probe force microscopy (KPFM), and density functional theory (DFT) calculations collectively elucidate the interplay among interfacial charge separation, transport, and surface reaction kinetics, thereby accounting for the markedly enhanced performance. These results underscore dual‐cocatalyst engineering as an effective strategy to optimize coupled photocatalytic energy conversion by regulating hole‐utilization pathways.