MgIn2S4-decorated MOF-derived C/N–CeO2 nanorod heterojunctions as efficient photocatalysts towards H2O2 production reactions and H2 evolution reactions

Abstract

The design of defect-induced metal oxide–based photocatalysts with precise reactive sites, facilitating photogenerated charge migration, and strong visible light harvesting capacity is not straightforward. Herein, Ce-MOF and MgIn₂S₄ (MIS) were used as precursor materials to prepare hierarchical C/N–CeO₂/MIS, 1D–2D heterostructures using a facile in situ hydrothermal technique. Among all the heterojunction composites, 20 wt% MIS-decorated C/N–CeO₂ (MC-2) nanohybrids displayed the highest H₂O₂ and H₂ evolution rates (2520.4 μmol h⁻¹ g⁻¹ and 419.2 μmol h⁻¹) with conversion efficiencies of 0.11% and 6.73%, respectively. A higher Ce(III) atomic fraction and more oxygen vacancies on the surface of MC-2 were shown by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electron paramagnetic resonance (EPR) study. In addition, HRTEM and surface charge analysis confirm the robust interfacial interaction between C/N–CeO₂ and MIS. The mechanism of charge transfer and separation within the Z-scheme heterojunction was studied by ultraviolet photoelectron spectroscopy (UPS) and electron spin resonance (ESR) spectroscopy. This research opens up a new avenue for the rational design of inexpensive MOF-derived metal oxide–based photocatalysts for various photocatalytic applications.