Fabrication of N/K-doped TiO2-Ag nanospheres with efficient charge transfer for enhanced photocatalytic CO2 reduction into CH4

Solar-driven CO 2 reduction into hydrocarbon fuels has a great potential for mitigating the issues of greenhouse effect and fossil energy crisis we are currently facing. It is a great challenge for visible-light-driven photocatalytic CO 2 reduction into CH 4 with high selectivity and conversion efficiency. Herein, we report a synthesis of N/K-doped TiO 2 nanospheres with Ag nanoparticles decoration (N/K-TiO 2 -Ag) by a solvothermal method and study its photocatalytic CO 2 reduction performance. It is found that the N/K-TiO 2 -Ag composite exhibits superior photocatalytic CO 2 reduction into CH 4 yield and selectivity than K-TiO 2 and N/K-TiO 2 . Indeed, the N/K-TiO 2 -Ag-0.5 sample shows the highest CH 4 yield with rate of 113.84 μmol g −1 h −1 and selectivity of CH 4 (93.71%) under light irradiation. The enhancement might be attributed to the synergy of N/K doping and silver loading. In particular, the N/K doping and the Ag cocatalysts introducing triggered improvement of solar energy utilization and charge separation as well as Ag-induced SPR effect and the K + -induced redistribution of photogenerated charge carriers cooperatively promotes photocatalytic CO 2 conversion into CH 4 . It is expected this work would offer a guide for rational design of K/TiO 2 -based photocatalyst for selectively converting CO 2 into fuels.