One-step photodeposition of spatially separated CuOx and MnOx dual cocatalysts on g-C3N4 for enhanced CO2 photoreduction

The rapid recombination of photogenerated carriers of photocatalysts greatly limits their actual application in CO2 conversion into valuable chemicals. Herein, dual CuOx and MnOx cocatalysts are decorated on g-C3N4 nanosheets via a one-step photodeposition strategy. Benefiting from the repulsion between Cu2+ and Mn2+ cations, a novel g-C3N4-based heterostructure loaded with spatially separated CuOx and MnOx nanoparticle dual cocatalysts has been successfully fabricated. Cu favors the trapping of electrons, while MnOx tends to collect holes. Moreover, the Cu2O/g-C3N4 p–n heterojunction also accelerates the charge separation. As a result, the photogenerated holes and electrons flow into and out of the photocatalyst, respectively, resulting in enhanced charge separation for achieving efficient CO2 photoreduction over CuOx/g-C3N4/MnOx. Accordingly, the optimized CuOx/g-C3N4/MnOx exhibits an improved CO production rate of 5.49 μmol g−1 h−1, which is 27.5 times higher than that of bare g-C3N4.