Novel β-Ag2MoO4/g-C3N4 heterojunction catalysts with highly enhanced visible-light-driven photocatalytic activity

Abstract

The kernel of photocatalysis research is the development of catalysts with remarkable photocatalytic activity. g-C₃N₄ has attracted much interest as a new and promising photocatalyst, but further modification and improvement of g-C₃N₄ is urgently needed. Herein, we report a novel β-Ag₂MoO₄/g-C₃N₄ heterojunction system with highly enhanced visible-light-driven photocatalytic activity. β-Ag₂MoO₄ nanoparticles were in situ loaded onto thin g-C₃N₄ nanosheets to make these heterojunction photocatalysts. The photocatalytic activities of these heterojunctions and the relevant samples were investigated by degrading Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) under visible light irradiation (λ > 400 nm). β-Ag₂MoO₄/g-C₃N₄ heterojunctions were found to be much more active than pristine β-Ag₂MoO₄, g-C₃N₄, or a mechanical mixture of both in the degradation of organic pollutants. The optimal catalyst had a β-Ag₂MoO₄/g-C₃N₄ mass ratio of 37.5%. Through relevant characterization, the upgraded photocatalytic activities of the β-Ag₂MoO₄/g-C₃N₄ heterojunctions were mainly attributed to the efficient separation of photogenerated charge carries. Superoxide radical anions (˙O₂⁻) and photogenerated holes (h⁺) were found to be the main active species.