Study on the effect and mechanism of Ag and Bi2MoO6 modification on the CO2 photo-thermal reduction performance of g-C3N4 catalysts with localized surface plasmon resonance

As a promising future energy material, g-C3N4 as a CO2 photo-thermal-reduction catalyst can effectively convert CO2 to renewable fuel, but the low yield and low product selectivity significantly limit its further development and application. Herein, Ag and Bi2MoO6 were loaded separately or together on g-C3N4 catalysts by photo-deposition and solvothermal synthesis methods, wherein the conversion efficiency of the g-C3N4 catalyst co-loaded with 0.5% Ag and 10% Bi2MoO6 was the highest (CO yield = 50.77 μmol g−1 h−1, CO selectivity = 96.98%). Characterization shows that the co-loading of Ag and Bi2MoO6 reduces the band gap of g-C3N4, improves the light absorption performance, and promotes the photoelectron transfer and CO2 adsorption, which may be attributed to the LSPR of Ag and the Z-scheme heterojunction between g-C3N4 and Bi2MoO6. The results of in situ DRIFTS and DFT calculations are consistent with the above conclusion and show that Ag loading effectively reduces the energy barrier of each intermediate state. This thesis aims to provide data support and theoretical guidance for optimal design of g-C3N4 catalysts.