Efficient Z-scheme g-C3N4/MoO3 heterojunction photocatalysts decorated with carbon quantum dots: improved visible-light absorption and charge separation

摘要

Z-scheme heterojunction photocatalysts based on g-C3N4 generally need to recombine g-C3N4 and a wide bandgap semiconductor. This structure is limited by the large bandgap of the constituent material, which can effectively suppress carrier recombination while limiting the absorption of visible light. Due to the superior up-conversion photoluminescence properties of the carbon quantum dots (CQDs), this dilemma can be solved ingeniously by adding CQDs to the composite. Moreover, the charge reservoirs of CQDs are conducive to the charge carrier separation effect. In this work, a novel CQDs-modified Z-type photocatalyst is constructed and the successful implantation of CQDs is demonstrated. The composite catalyst exhibits broad-spectrum response to visible light and the overall performance is obviously superior to that of the binary MoO3/g-C3N4 heterojunction. The high efficiency and versatility of the degradation imply that the newly prepared CQDs/g-C3N4/MoO3 is a versatile photocatalyst for the removal of various target pollutants in the environment.