Enhanced photodegradation by RGO/ZnO core-shell nanostructures

Abstract

RGO/ZnO core-shell nanostructures were synthesized by a simple sol-gel method and then heated to 500℃at 4 × 10−3 Torr to remove moisture. The photodegradation efficiency and its related rate constant (k) were evaluated by using it in the degradation of methylene blue (MB, C16H18N3ClS) solution. The RGO/ZnO CSNs has a high photodegradation efficiency, which is attributable to the increased specific surfaces area, enhanced absorption of the visible light (λ = 380−780 nm), the defect levels of VO2- and Zn2+i which supply the extra electrons, highly effective charge-carrier transfer, and localized surface plasmon resonance (LSPR) at the interface between dielectric ZnO and electric RGO, resulting in the effective absorbance of MB molecules and an increase in the electron-hole lifetime, and a consequent increase in photodegradation efficiency. A critical loading of 800 ppm RGO was identified and found to provide an efficiency of higher than 93 % in 15 min under visible radiation.