Facile solvothermal fabrication of cubic-like reduced graphene oxide/AgIn5S8 nanocomposites with anti-photocorrosion and high visible-light photocatalytic performance for highly-efficient treatment of nitrophenols and real pharmaceutical wastewater

Abstract

Although Ag-containing semiconductors as effective photocatalysts have attracted significant concern because of the unique photosensitivity, their visible-light photocatalytic activities are still not satisfactory, and usually suffer from photocorrosion. In this study, cubic-like reduced graphene oxide/AgIn5S8 (rGO/AIS) nanocomposites were fabricated via a mild solvothermal method, and employed to photodegrade nitrophenols (2-nitrophenol and 4-nitrophenol) and dispose of real pharmaceutical wastewater under visible-light illumination. All the rGO/AIS nanocomposites exhibited higher photocatalytic activities than that of pure AIS, and the photocatalytic activities of rGO/AIS is related with different rGO content. The optimized 1% rGO/AIS displayed the highest photocatalytic activities with 91% 4NP removal and 93.2% 2NP removal efficiency in 120 min, which can be ascribed to the largest specific surface area, enhanced light absorption, as well as the most efficient separation and transfer of photogenerated charges. Most importantly, H2O2 aided photocatalysis of 1% rGO/AIS can effectively deal with real pharmaceutical industry wastewater with 89% COD removal. Additionally, 1% rGO/AIS exhibits excellent reusability in four cycles due to its anti-photocorrosion ability, stable crystal structure, surface composition and chemical valence state. The above results open up new horizons for improving the photocatalytic activity and stability of AIS, providing a green method for processing actual pharmaceutical wastewater references.