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

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, O 2 firstly reduces to superoxide radical (O 2 •-), then transforms into hydrogen peroxide (H 2 O 2) via reduction and protonation process, finally reduces into •OH. In this study, OH/C V -CN, hydroxyl groups (–OH) and carbon vacancies (C V) 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 C V into CN during roasting process. C V , active sites for reducing O 2 to O 2 •-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O 2 •- and avoids the polymerization induced by •OH. Therefore, –OH and C V in OH/C V -CN synergistically facilitate the photomineralization of phenol. [Display omitted] • –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into carbon nitride through adjusting the electron distribution on the adjacent heptazine. • C V , locating on the same heptazine ring with –OH, realize the rapid transformation of O 2 to O 2 •- as O 2 adsorption sites. • O 2 •- in-situ mineralize phenol instead of reducing to •OH profited from the shorter distance between O 2 •- and adsorbed phenol on OH/C V -CN than CN, which facilitates effective photomineralization of phenol and cleverly prevent forming polymer. 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, O 2 firstly reduces to superoxide radical (O 2 •-), then transforms into hydrogen peroxide (H 2 O 2) via reduction and protonation process, finally reduces into •OH. In this study, OH/C V -CN, hydroxyl groups (–OH) and carbon vacancies (C V) 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 C V into CN during roasting process. C V , active sites for reducing O 2 to O 2 •-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O 2 •- and avoids the polymerization induced by •OH. Therefore, –OH and C V in OH/C V -CN synergistically facilitate the photomineralization of phenol. [ABSTRACT FROM AUTHOR]