Design of faceted 0D/1D CeO2/ZnO S-scheme heterostructures for solar-driven methanol production

Abstract

Efficient solar-driven conversion of CO2 into value-added chemical presents a promising approach to addressing climate change and energy scarcity. However, sluggish charge carrier kinetics remain a significant barrier to effective CO2 photoreduction. In this study, a solvothermal method is employed to synthesize facet-engineered CeO2/ZnO nanorod (NRs) S-scheme heterojunctions for the selective photoreduction of CO2 to methanol under mild conditions. Comprehensive characterization confirms the successful deposition and stability of CeO2 nanoparticles on the surface of ZnO NRs. Among the synthesized photocatalysts, the composite with 0.2 mmol CeO2 exhibits the best performance, yielding 111 µmol·g₋1, 176 µmol·g₋1, 311 µmol·g₋1, and 304 µmol·g₋1·h₋1 for H2, CO, CH4, and CH3OH, respectively, with a notable CO2 selectivity of approximately 89 %. Mechanistic analysis reveals that optimized CeO2 loading induces an internal electric field, facilitating an S-scheme heterojunction charge-transfer pathway that enhances electron mobility from the ZnO NRs to CeO2. In-situ FT-IR spectroscopy further identifies key intermediates (HCOO* and H3CO*) involved in the transformation of CO2 to CH3OH. This work demonstrates a novel photocatalyst design that leverages precise CeO2 loading onto ZnO NRs, offering a promising strategy for efficient and selective CO2 photoreduction. © 2025 The Author(s)