Nitrogen-doped carbon dot-modified Ag3PO4/GO photocatalyst with excellent visible-light-driven photocatalytic performance and mechanism insight†
Abstract
In this paper, an all solid Z-scheme Ag3PO4/GO/NCD photocatalyst has been prepared through anchoring nitrogen-doped carbon dots (NCDs) on the Ag3PO4/GO (GO = graphene oxide) composite. The Ag3PO4/GO/NCD photocatalyst exhibits excellent photocatalytic activity for the degradation of organic pollutants, methylene blue (MB), rhodamine B (RhB) and phenol, under visible-light irradiation. The pollutants MB (10 mg L−1), RhB (10 mg L−1) and phenol (50 mg L−1) could be efficiently degraded within 2.5 min, 5 min and 120 min, respectively, which are much better than that over Ag3PO4 and Ag3PO4/GO, indicating that the introduction of NCDs can further improve the photocatalytic activity of Ag3PO4/GO. Moreover, after four photocatalytic cycles, the photocatalytic activity of Ag3PO4/GO/NCDs shows only a slight decrease, demonstrating high photocatalytic stability. It is revealed that GO in the photocatalyst acts as a semiconductor and forms a Z-scheme heterojunction with Ag3PO4, while NCDs improve the oxygen activation, enhance the light harvesting capacity and serve as the reaction sites during the photocatalytic process. This study highlights the potential application of highly efficient NCD-modified photocatalysts in waste water purification.