Preparation of highly efficient Ni-doped layered perovskite grafted graphene oxide NixSr1-xTiO3-RGO heterojunction photocatalyst with enhanced visible-light photocatalytic activity for MB degradation

Highlights: • 2D lamellar perovskite improves the separation of electron-hole pairs. • The doping of Ni particles broadens the light response range. • NixSr_1-xTiO₃ was successfully loaded on RGO with a larger specific surface area to improve its dispersion. • Heterojunction layered catalysts show better performance. Two-dimensional layered semiconductor photocatalysts have attracted much attention due to their excellent performance. Layered photocatalyst, however, generally has low visible-light utilization and is easy to self-polymerize. In this study, layered photocatalyst Ni_xSr_1-xTiO₃ was prepared by doping Nickelin perovskite, and then loaded on RGO with a larger specific surface area. Heterojunction photocatalyst with high performance was successfully prepared. The results show that doping Ni will introduce an occupied energy level between the band gaps, effectively reducing the forbidden bandwidth, and the wavelength of 600 nm still has a high optical response. Much elevated photocatalytic degradation was investigated after further loading Ni_xSr_1-xTiO₃ onto RGO. As a carrier, RGO can improve the self-polymerization of the catalyst and form heterojunction with NixSr1-xTiO₃. The transfer of photogenerated carriers is promoted relying on the potential difference between the two sides of the heterojunction interface and the electron transport channel of RGO. We also noticed that the unique amphoteric molecular properties of RGO can improve the dispersion of Ni_xSr_1-xTiO₃-RGO in dye wastewater. To sum up, the synergistic effect of reducing band gaps, inhibiting heterojunction structure and improving dispersion are the reasons for more efficient activity.