Synthesis of flower-like MoS2/g-C3N4 nanosheet heterojunctions with enhanced photocatalytic reduction activity of uranium(VI)

The conversion of soluble hexavalent uranium into insoluble tetravalent uranium from aqueous solution by photocatalysis is an attractive method to eliminate radioactive pollution. In this study, flower-like MoS2/g-C3N4 nanosheet heterojunctions (FMCN) were synthesized as a catalyst for the reduction of U(VI). The characterization by various methods (e.g., XPS, TEM, UV–Vis, EIS, and PL) clearly confirmed that the flower-like MoS2 was loaded on the g-C3N4 nanosheets and that the successful construction of the heterojunction widened the visible light absorption range, promoting the charge transfer and enhancing the separation efficiency of photoinduced electron-hole pairs. The FMCN containing 5% MoS2 (0.05-FMCN) exhibited the highest photocatalytic reduction activity of U(VI), which was significantly higher than that of g-C3N4. Furthermore, 0.05-FMCN revealed considerable stability under visible light irradiation. Due to its simple synthesis and enhanced photocatalytic reduction activity, the FMCN is expected to be a promising candidate catalyst for eliminating radioactive contamination.