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

Abstract

The rapid recombination of photogenerated carriers of photocatalysts greatly limits their actual application in CO₂ conversion into valuable chemicals. Herein, dual CuO_x and MnO_x 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 CuO_x and MnO_x nanoparticle dual cocatalysts has been successfully fabricated. Cu favors the trapping of electrons, while MnO_x 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 CuO_x/g-C₃N₄/MnO_x. Accordingly, the optimized CuO_x/g-C₃N₄/MnO_x 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.