In situ construction of Cs3Sb2Br9/CeO2 heterojunction for efficient photooxidation of 5-hydroxymethylfurfural

Abstract

Halide perovskite-based heterojunctions have attracted significant attention in solar energy conversion, yet their performance is often limited by inefficient interfacial charge separation. Herein, we address this challenge through deliberate oxygen vacancies (OVs) engineering by constructing a Cs3Sb2Br9/CeO2 heterojunction via a facile in situ growth route for efficient photocatalytic conversion of 5hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). It is revealed that, beyond facilitating the in situ nucleation and growth of Cs3Sb2Br9 nanocrystals to establish interfacial intimate interaction, the abundant OVs on the surface of CeO2 also function as active sites for the adsorption and activation of molecular oxygen. The enhanced spatial separation of photogenerated charge carriers and promoted generation of reactive oxygen species (ROS) contribute a lot to the HMF photooxidation. The optimized heterojunction achieves an exceptional DFF production rate of 6226.1 μmol g⁻¹ h⁻¹ with 100% selectivity, surpassing the performance of most previously reported photocatalysts. This work establishes a novel interfacial design paradigm for OVs-mediated lead-free perovskite heterojunctions. Simple but effective, this approach simultaneously manages charge transfer and surface catalysis, significantly advancing the photocatalytic valorization of biomass.