PtCu alloy cocatalysts for efficient photocatalytic CO2 reduction into CH4 with 100% selectivity

In this paper, PtCu alloys with varying Pt/Cu ratios were deposited onto TiO2 nanocrystals to selectively photoreduce CO2 into CH4. The experimental results show that the appropriate Pt/Cu deposition ratio significantly improves CH4 production with 100% selectivity. The PtCu alloy not only effectively promotes the separation/transfer of photogenerated charges, but is also beneficial for the adsorption of CO2 and the formation and activation of intermediates (CO2-, *COOH, *CO, and *CHO). Furthermore, two paths for *CO formation are observed on the surface of PtCu/TiO2, providing sufficient *CO for CH4 generation. Density functional theory calculations show that the synergistic effect of PtCu reduces the activation energy barriers of *CO2 and *CHO and inhibits the desorption of *CO, which simultaneously optimizes the efficiency and selectivity of CO2 reduction. These findings may provide new insights for exploring alloy cocatalysts for regulating the product selectivity of photocatalytic CO2 reduction.