Carbon and cobalt co-doped carbon nitride for superior generation of singlet oxygen via peroxymonosulfate activation induced by recyclable cobalt redox

In this work, a carbon and cobalt co-doped carbon nitride (Co 0.04 -CCN 0.25 ) catalyst was synthesized for superior generation of singlet oxygen ( 1 O 2 ) via peroxymonosulfate (PMS) activation. The findings indicate that carbon self-doping not only reduces the interfacial charge transfer resistance but also constructs efficient electron transfer channels between g-C 3 N 4 support and cobalt active sites. This directional electron transfer increases the electron density of cobalt species, which can accelerate the Co(II)/Co(III) redox cycle. As a result, the optimized Co 0.04 -CCN 0.25 catalyst achieves 100% of bisphenol A (BPA) degradation within 6 min under ambient conditions. Mechanistic investigations reveal that the singlet oxygen is the dominant reactive oxygen species (ROS) at the Co active site in the Co 0.04 -CCN 0.25 , which presents a desirable and recyclable redox pair of Co(II)/Co(III). Furthermore, the modified catalyst exhibits excellent pH tolerance over a broad range and strong anti-interference ability against co-existing anions and humic acid in aqueous solutions. Liquid chromatography-mass spectrometry (LC-MS) analysis and ecotoxicity assessment further demonstrate that the toxicities of BPA degradation intermediates are significantly reduced during the oxidation process. Therefore, this study provides a promising and practical strategy for designing high-efficient C 3 N 4 -based catalyst of PMS activation. Download: Download high-res image (175KB) Download: Download full-size image