Degradation of Methylene Blue in the Photo-Fenton-Like Process with WO3-Loaded Porous Carbon Nitride Nanosheet Catalyst

Abstract

The catalytic capability of original carbon nitride (CN) is limited by a small specific surface area and high electron–hole recombination rate. In this study, WO3-loaded porous carbon nanosheets (MCA-CN/WO3) were synthesized by thermal treatment with melamine, cyanuric acid and WCl6. The MCA-CN/WO3 could degrade 98% of the methylene blue (MB) within 30 min in the photo-Fenton-like process, displaying better catalytic activity than the original CN (30%), pure MCA-CN (63%) and original CN/WO3 (87%). The results of photoluminescence and electrochemical impedance spectroscopy demonstrated that the Z-scheme heterojunction of MCA-CN/WO3 inhibited the recombination of electrons and holes. In addition, the porous nanosheet structure accelerated the electron transfer and provided abundant active sites for MB degradation. A radical quenching experiment indicated that the Z-scheme heterojunction facilitated the decomposition of H2O2 to produce 1O2 for MB degradation. The possible degradation pathways of MB were proposed.