Design of faceted 0D/1D CeO2/ZnO S-scheme heterostructures for solar-driven methanol production
Hazina Charles, Plassidius J. Chengula, Jiyeon Seo, Caroline Sunyong Lee
Abstract
Efficient solar-driven conversion of CO 2 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 CO 2 photoreduction. In this study, a solvothermal method is employed to synthesize facet-engineered CeO 2 /ZnO nanorod (NRs) S-scheme heterojunctions for the selective photoreduction of CO 2 to methanol under mild conditions. Comprehensive characterization confirms the successful deposition and stability of CeO 2 nanoparticles on the surface of ZnO NRs. Among the synthesized photocatalysts, the composite with 0.2 mmol CeO 2 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 H 2 , CO, CH 4 , and CH 3 OH, respectively, with a notable CO 2 selectivity of approximately 89 %. Mechanistic analysis reveals that optimized CeO 2 loading induces an internal electric field, facilitating an S-scheme heterojunction charge-transfer pathway that enhances electron mobility from the ZnO NRs to CeO 2 . In-situ FT-IR spectroscopy further identifies key intermediates (HCOO* and H 3 CO*) involved in the transformation of CO 2 to CH 3 OH. This work demonstrates a novel photocatalyst design that leverages precise CeO 2 loading onto ZnO NRs, offering a promising strategy for efficient and selective CO 2 photoreduction.