CQDs improved the photoelectrocatalytic performance of plasma assembled WO3/TiO2-NRs for bisphenol A degradation.

Abstract

Carbon quantum dots (CQDs) have been supported on WO3/TiO2-NRs using a hydrothermal method and a novel CQDs/WO3/TiO2-NRs composite formed via dielectric barrier discharge. The composite electrodes were characterized using morphology, structural, optical and electrochemical analysis. The CQDs were successfully prepared on the composite electrode with the highest photocurrent density reaching 2.51mA·cm-2 under UV-visible light irradiation (100mW·cm-2) and an applied voltage of 0.6V vs. Ag/AgCl. The CQDs/WO3/TiO2-NRs electrode exhibited a good degradation effect toward bisphenol A (BPA) (75.66 %) combined with the production of hydrogen (0.89mmol) in Na2SO4 system after 2h of the photoelectrocatalytic (PEC) reaction and the BPA degradation rate reached 100 % after 7min of reaction in both simulated and real seawater. The CQDs/WO3/TiO2-NRs exhibited excellent stability and efficient PEC performance in which the CQDs acted as electron reservoirs to capture and promote charge separation. Our analysis of intermediates of BPA degradation indicated the possible degradation pathways that mainly formed BPA polymers in the Na2SO4 system or chlorinated compounds in the high chloride salt system.