Ni(OH)₂-Decorated Zn₃In₂S₆@ZIF-L Dual-S-Scheme Heterostructure for Cooperative Photocatalytic CO₂ Reduction Coupling with Benzyl Alcohol Oxidation

Abstract

Photocatalytic CO2 reduction coupling with selective oxidation into high-value fuels and chemicals is a promising route but is challenging due to the relatively low reactivity. Herein, the ternary Ni(OH)2/Zn3In2S6@ZIF-L heterostructure is prepared by an in situ growth and electrostatic interaction strategy for simultaneous photocatalytic CO2 reduction and benzyl alcohol oxidation. The incorporation of Ni(OH)2 in the ternary heterostructure not only significantly accelerates the electron–hole separation and improves charge transfer efficiency but also enhances CO2 adsorption ability, thus boosting the activity for photoredox coupling reaction. The optimized Ni(OH)2/Zn3In2S6@ZIF-L-3 reaches excellent CO and benzaldehyde production rates up to 344.66 and 11,560 μmol·g–1, respectively, outperforming other previously comparable photocatalysts. The remarkably enhanced performance is attributed to excellent photogenerated charge transfer ability, two interfacial electric fields built at the interface, and a dual-S-scheme charge transfer pathway from ZIF-L and Ni(OH)2 to Zn3In2S6. The photocatalytic mechanism reveals that the photogenerated electrons that accumulated on the conduction band of Zn3In2S6 participate in the CO2 reduction, and simultaneously, the reserved holes on the valence band of Ni(OH)2 achieve the benzyl alcohol oxidation. This work would offer a guideline for creating dual-S-scheme heterostructures for photocatalytic CO2 reduction coupling with selective oxidation into high-value chemicals.