Constructing photocatalysis-self-Fenton system over a defective twin C3N4: In-situ producing H2O2 and mineralizing organic pollutants

A new strategy to realize efficient removal of organics from water through photo-self-Fenton was investigated. Characterizations and calculations demonstrated that a novel twin carbon nitride with abundant surficial N-defects and compressed π-π layer stacking can be constructed by thermal polymerization of urea under suitable basicity. Synergistically, the twins exhibited an in-situ H2O2 producing at a rate as high as 26.36 mM h−1 g−1 at 420 nm that exceeded most reported C3N4, and their mineralization rates for Tetracycline Hydrochloride, Bisphenol A, Ciprofloxacin, and Rhodamine B reached 8.8, 15.2, 9.1, and 13 times higher than that of pristine C3N4. It is concluded that enriching both of photogenerated electrons and molecular oxygens on specific sites plays a crucial role during photocatalysis-self-Fenton process. Particular attentions have to be paid to build structures achieving one and two-electron reduction of O2, and activation of H2O2 to •OH simultaneously.