Preparation of a ZnIn2S4–AlOOH composite for the photocatalytic reduction of CO2 to CO

Abstract

Photocatalytic reduction of CO₂ to high value-added chemicals and fuels has received widespread attention. However, the higher thermodynamic stability of CO₂ greatly limits its conversion efficiency. Frustrated Lewis pairs (FLPs) have been well-established to be very effective in CO₂ activation. In this work, we prepared ZnIn₂S₄–AlOOH (ZIS–AlOOH) composites for visible-light-driven CO₂ reduction. The Lewis basic O_Hv sites on the AlOOH surface (one H removed from OH) and an adjacent Lewis acidic unsaturated Al site (Al³⁺_unsatur.) form the FLPs. The composite structure facilitated light absorption, CO₂ adsorption activation, and separation of photogenerated carriers, thus improving the CO₂ photoreduction activity (CO generation rate of 510.3 μmol g⁻¹ h⁻¹), and suppressing hydrogen evolution with the CO/H₂ ratio increasing from 0.38 for ZnIn₂S₄ (ZIS) to 0.84 for ZIS–AlOOH. This work elucidates a rational strategy for the construction of efficient photocatalysts and provides insight into the mechanism of the photocatalytic CO₂ reduction reaction.