Developing Atomically Thin Li_1.81H_0.19Ti₂O₅·2H₂O Nanosheets for Selective Photocatalytic CO₂ Reduction to CO

Solar-driven CO₂ conversion to carbon-based fuels is an attractive approach to alleviate the worsening global climate change and increasing energy issues. However, exploring and designing efficient photocatalysts with excellent activity and stability still remain challenging. Herein, layered Li_1.81H_0.19Ti₂O₅·2H₂O (LHTO) nanosheets were explored as the photocatalyst for photocatalytic CO₂ reduction, and atomically thin LHTO nanosheets with one-unit-cell thickness were successfully constructed for photocatalytic CO₂ reduction. The atomically thin LHTO nanosheets exhibited excellent performance for CO₂ photoreduction to CO, with a yield rate of 4.0 μmol g^-1 h^-1, a selectivity of 93%, and over 25 h photostability, dramatically outperforming the bulk LHTO. The better performance of the atomically thin LHTO nanosheets was experimentally verified to benefit from more sites for CO₂ adsorption, faster electron transfer rate, and a more negative conduction band edge compared with bulk LHTO. This work provided a methodological basis for designing more efficient photocatalytic CO₂ reduction catalysts.