Photo-induced Au-Pd alloying at TiO2 {101} facets enables robust CO2 photocatalytic reduction into hydrocarbon fuels

While photocatalytic conversion of CO2 is a promising approach for the production of renewable fuels, it has always suffered from low yield and poor selectivity, thus the artful design of catalytic sites holds the key to addressing this issue. Herein, we construct Au-Pd alloy catalytic sites on TiO2 {101} facets for robust CO2 conversion to hydrocarbons through a photo-induced alloying strategy. The Au-Pd alloy provides abundant sites for CO2 adsorption and activation, in which the uniformly dispersed Pd atoms could synchronously act as hydrogenation centers. The synergistic effect of Au and Pd, in combination with the photogenerated electron-rich nature of TiO2 {101} facets, is proposed to account for the highly efficient CO2 reduction. Remarkably, the optimal sample has achieved a high selectivity of 85% (71%: CH4, 14%: C2H4 and C2H6) for hydrocarbons with an evolution rate of 14.3 mu mol g(-1) h(-1). This work provides new insights into the design of active sites for CO2 photoreduction, and highlights the significance of surface structure engineering in improving selectivity towards high grade carbon products.