摘要
Developing a bifunctional photocatalytic system that combines efficient hydrogen evolution and hydrogen peroxide generation is of great significance for achieving solar-driven water splitting and green oxidant synthesis. In this study, a cobalt phosphide (CoP) cocatalyst with metalloid conductivity and porous structure was prepared by phosphorizing ZIF-67, and then composited with MnCdS solid solution via a one-pot hydrothermal method, successfully constructing a MnCdS@ZIF/P (MCS@Z/P) Schottky junction photocatalyst with intimate interfacial contact. The Mn doping strategy effectively regulated the band structure of CdS, not only narrowing the bandgap from 2.27 eV to 2.17 eV but also shifting the valence band maximum upward, thereby significantly enhancing visible light absorption and hole oxidation potential. After contacting with high-work-function CoP, a strong built-in electric field is formed at the interface, efficient driving directional transfer of photogenerated electrons from MnCdS to CoP. Under visible light irradiation, the optimized MCS@10Z/P catalyst exhibits excellent photocatalytic activity for both H 2 evolution (42.33 mmol·g −1 ·h −1 ) and H 2 O 2 production (1951.09 μmol·g −1 ·h −1 in air) in two independent reaction systems. Mechanistic studies reveal that the introduction of CoP not only serves as an efficient electron transport medium, but also shifts the oxygen reduction pathway from an inefficient single-electron process to a highly efficient two-electron dominant pathway by optimizing the *OOH intermediate adsorption free energy. The Gibbs free energy(ΔG H ) of the optimal sample is reduced to 0.13 eV, which significantly reduces the reaction energy barrier. This work provides new insights into the design of efficient bifunctional Schottky junction photocatalysts based on MOF-derived materials.
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