Selective production of singlet oxygen for enhanced photocatalytic degradation performance of organic pollutants by C/COF coupled with persulfate.

Photocatalysis based on porous and stable sp carbon-linked COF materials is a promising technology to deal with energy shortage and environmental pollution. In this work, C/COF composite was prepared and applied to the photocatalytic degradation of organic pollutants by coupling with persulfate. The degradation efficiencies of lomefloxacin (LOMH) and trichloromethane (TCM) achieved 80.4 % and 74 % by the proposed system. The separation of photogenerated electron-hole pairs, electron migration and the photocatalytic activity of the composite were analyzed through XPS technology, transient fluorescence technology and electrochemical tests. The results of active species capture and electron spin resonance experiments proved that singlet oxygen (O) was selectively generated and played a leading role with holes (h), contributing to the oxidation of the targets pollutants. DFT calculation results showed that the composite of C/COF has enhanced adsorption strength of both target pollutant and O, leading to a better photocatalytic oxidation effect. This work provided an efficient, economical and environmentally friendly way to remove organic pollutants driven by clean light energy, which shows practical application potential and is compatible with the "cost reduction and efficiency increase" strategy.