SnTa2O6: A novel CO2 reduction photocatalyst with nearly 100% CO selectivity

Photocatalysis is a green and effective measure for CO2 utilization. Herein, we synthesized a novel SnTa2O6 nanosheet photocatalyst via a simple melting heat treatment and first applied it to CO2 photoreduction with water. Interestingly, as the heating time extended, the synthesized ternary oxides of SnII changed from Sn2Ta2O7 octahedrons to SnTa2O6 nanosheets, which effectively improved the separation efficiency of photogenerated charges and increased reactive active sites. Density functional theory calculations and temperature programmed desorption showed that CO2 is more easily adsorbed and activated on SnTa2O6 than on Sn2Ta2O7. Under full-spectrum illumination, the CO yield of Sn-25 (SnTa2O6) was 16.8 times that of Sn2Ta2O7 with good stability. The high CO selectivity and reaction stability of SnTa2O6 can be ascribed to the lower potential barrier of CO formation and weaker interaction between CO and SnTa2O6. This research will stimulate in-depth research on the use of new and efficient tantalates for CO2 photoreduction.