Zn0.5Cd0.5Se quantum dot-integrated MOF-derived C/N–CeO2 photocatalyst for enhanced H2O2 production and O2 evolution reactions†

Abstract

Herein, a rational strategy is presented to reduce the sluggish reaction kinetics and inefficient charge carrier separation of heterojunctions while enhancing their opto-electronic properties. A 1D–0D heterojunction, i.e., MOF-derived C/N–CeO₂/Zn_0.5Cd_0.5Se quantum dot (CZCSe-1) hybrid material, was constructed to address the limitations associated with the H₂O₂ production and O₂ evolution reactions through a facile reflux treatment. As anticipated, the optimised CZCSe-1 composite exhibited an impressive H₂O₂ production rate of 2820.43 μmol g⁻¹ h⁻¹, which was 1.7- and 2.1-fold higher than those of pristine C/N–CeO₂ and ZCSe, respectively, and it exhibited stability up to four cycles. Additionally, an O₂ evolution rate of 234.89 mmol g⁻¹ h⁻¹ was recorded for CZCSe-1, which showed superior activity over other materials previously reported in the literature. It was revealed that the outstanding photocatalytic performance was attributed to the effective anchoring of 0D ZCSe onto vacancy-rich C/N–CeO₂ nanorods, displaying improved charge separation as obtained from the Pl, EIS, TPC and maximized redox capability analyses. The charge transfer dynamics in the CZCSe-1 composite via the S-scheme heterojunction was further investigated through free radical detection (ESR analysis) and work function study (VB-XPS). This work offers a new approach for optimizing economic metal oxide-based photocatalysts for H₂O₂ production and other applications.