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

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 (Al-unsatur.(3+)) 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 mu mol g(-1) h(-1)), and suppressing hydrogen evolution with the CO/H-2 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.