Integrating Spatially Separated Redox Sites into Nanosheet-Assembled Hollow Superstructures for CO2-Alcohol Photoredox Catalysis

Abstract

Photocatalytic CO2 reduction coupled with alcohol oxidation enables the simultaneous production of solar fuels and value-added chemicals, yet redox-site interference on a single photocatalyst remains a key efficiency limitation. Herein, we install spatially separated redox sites into a nanosheet-assembled hollow superstructure by constructing Cd(OH)2/CdS nanosheet-assembled hollow cubes (CdOH-S NSAHC) for efficient CO2-benzyl alcohol photoredox conversion. The built-in electric field at the heterointerface can drive photogenerated electrons and holes toward Cd(OH)2 and CdS domains, respectively, enabling CO2 reduction and benzyl alcohol oxidation to proceed at different catalytic regions. The electron-enriched Cd(OH)2 domains enhance the adsorption of CO2 and stabilize the *COOH intermediate, while the hole-enriched CdS domains promote the α-C–H activation of benzyl alcohol. Meanwhile, the nanosheet-assembled hollow architecture exposes the separated redox sites and provides open diffusion pathways. As a result, CdOH-S NSAHC delivers CO and benzaldehyde production rates of 1.04 and 3.65 mmol g–1 h–1, respectively, and achieves a syngas evolution rate of 5.85 mL h–1 under natural sunlight.