Regeneration of novel visible-light-driven Ag/Ag3PO4@C3N4 hybrid materials and their high photocatalytic stability

Novel visible-light-driven Ag3PO4@C3N4PO4 loaded with metal Ag were synthesised via an anion-exchange precipitation method and regenerated by H2O2 and NaNH3HPO4. The obtained Ag/Ag3PO4@C3N4 and regenerated Ag/Ag3PO4@C3N4 were characterised by XRD, XPS, SEM and UV–vis. The XRD and UV–vis results revealed that the crystal structure and light adsorption property of Ag/Ag3PO4@C3N4 were similar to that of regenerated Ag/Ag3PO4@C3N4. The XPS result showed that the metallic Ag0 deposited on the surface of Ag/Ag3PO4@C3N4 and regenerated Ag/Ag3PO4@C3N4. The Ag/Ag3PO4@C3N4 hybrids displayed remarkable photocatalytic activity and stability after regeneration. Compared with pure Ag3PO4 or C3N4, the Ag/Ag3PO4@C3N4 and regenerated Ag/Ag3PO4@C3N4 enhancement in the photodegradation rate towards methyl orange is observed over under visible light irradiation. The enhanced photocatalytic performance was attributed to the synergistic effect between Ag3PO4 and C3N4 and a small amount of Ag0 which suppresses the charge recombination during photocatalytic process. This work could provide new insights into the fabrication of high stability visible photocatalysts and facilitate their practical application in environment issues.