Enhanced photodegradation by RGO/ZnO core-shell nanostructures

•The visible light absorption of ZnO is obviously enhanced by the addition of the RGO nanosheets.•LSPR at the interface between RGO and ZnO is determined by the PL spectra.•LSPR and defect levels of VO2- and Zn2+i are contributed to enhance the MB photodegradation efficiency.•A critical loading of 800 ppm RGO is identified and provides an efficiency > 93% in 15 min.