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 OHv 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.