Improved photocatalytic CO2 conversion efficiency on Ag loaded porous Ta2O5

The photocatalytic efficiency of CO2 conversion into carbon-containing products relies on CO2 adsorption and activation on the surface of photocatalyst. Here, we developed a novel Ag loaded mesoporous Ta2O5 photo catalyst with high selectivity using a SiO2 template method along with an in-situ photodeposition method. Benefitting from the mesoporous structure, the amount of CO2 adsorbed by porous Ta2O5 is 10 times that of bulk Ta2O5 and the photogenerated electrons can capture and reduce CO2 more easily. Moreover, on the surface of Ta2O5, Ag particles work as active sites for CO2 reduction. After Ag loading, not only the charge separation efficiency was significantly promoted, but also the CO2 molecules on the surface of Ag were activated due to the formation of the strong interaction between Ag and CO2, thus facilitating the occurrence of CO2 reduction reaction. The CO and H-2 evolution rates of 1.0% Ag/Ta2O5 photocatalyst are 1.76 mu mlol g(-1) h(-1) and 0.18 mu mlol g(-1) h(-1), respectively, and the selectivity of CO2 reduction to CO reaches 90.7%. This work not only gives guidance for designing photocatalysts with high CO2 conversion efficiency but also provides insights into the roles of cocatalysts for CO2 reduction.