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

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.