Carbon quantum dots decorated BiVO4 quantum tube with enhanced photocatalytic performance for efficient degradation of organic pollutants under visible and near-infrared light

Abstract

Photocatalysis has been regarded as a sustainable and efficient technology for removing refractory pollutants in water. However, the performance of photocatalysis is usually limited by the fast recombination of photoinduced electron–holes and the narrow range of spectrum absorption. In this work, the visible-light-sensitive BiVO4 quantum tube (q-BiVO4) was decorated with the carbon quantum dots (CQDs) possessing unique upconversion fluorescence function for enhanced photocatalytic degradation of organic pollutants. Under visible light (λ > 420 nm) and even near-infrared light (λ > 700 nm) irradiation, the CQDs/q-BiVO4 composite displayed significantly enhanced performance compared with q-BiVO4 alone for the degradation of phenol and rhodamine B (RhB). The CQDs/q-BiVO4 with 2% CQDs loading exhibited the best performance, whose kinetic constants for phenol and RhB degradation were 3.0 and 2.4 times higher than that on q-BiVO4. The outstanding photocatalytic performance of CQDs/q-BiVO4 was ascribed to the quantum-sized BiVO4 and the dual function of CQDs, which not only served as the electron acceptor to separate the photoinduced electron–holes in q-BiVO4, but also improved the light absorption of q-BiVO4 through converting the near-infrared light into visible light. This work provides new insight into designing high-efficiency photocatalyst for enhanced environmental remediation.