Precisely regulating hydroxyl groups and carbon vacancies on carbon nitride for in-situ photomineralization of phenol

Abstract

Carbon vacancies Carbon nitride (CN) has been widely used in photomineralization of phenolic pollutants, during which avoiding the production of refractory polymers induced by hydroxyl radical (•OH) is the key. In CN photocatalytic system, O2 firstly reduces to superoxide radical (O2•-), then transforms into hydrogen peroxide (H2O2) via reduction and protonation process, finally reduces into •OH. In this study, OH/CV-CN, hydroxyl groups (–OH) and carbon vacancies (CV) co-modified CN, was designed for phenol photomineralization. –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing CV into CN during roasting process. CV, active sites for reducing O2 to O2•-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O2•- and avoids the polymerization induced by •OH. Therefore, –OH and CV in OH/CV-CN synergistically facilitate the photomineralization of phenol.