Bimetallic defect-engineered CoMoMOF modulates CdZnS for efficient hydrogen production from water/microplastic waste

Abstract

Defect regulation represents a crucial strategy for enhancing the separation efficiency of photogenerated carriers. In this study, a V-CoMoMOF (V-CMM) catalyst with Co and Mo dual-metal defects was synthesized via NaOH etching. It was then combined with CdZnS (CZS) to form a type-I heterojunction. The composite photocatalyst CZS/V-CMM-20% with bimetallic defects shows high-efficiency hydrogen evolution activity (1525 μmol) within 5 h, which is approximately twice that of CZS/CMM. Moreover, CZS/V-CMM-20% exhibits notable hydrogen evolution performance (258.9 μmol) from polyethylene terephthalate (PET) waste under the same conditions. Density functional theory (DFT) calculations demonstrate that the introduction of bimetallic defect sites markedly enhances charge-transfer dynamics and promotes the kinetics of surface catalytic processes. Moreover, the formation of type-I heterojunctions confines both electrons and holes within the same semiconductor, leading to localized exciton states that enhance light absorption. This study provides novel insights into the design of defect-engineered composite photocatalysts, and proposes a promising strategy for the conversion of waste plastics into hydrogen energy.