Photothermal-assisted S-scheme PDIs/C, N, S-CeO2 derived from MOF-808 (Ce) heterojunction for photocatalytic removal of antibiotics

In this research, an organic supermolecule self-assembly perylene diimides (PDIs) semiconductor was wrapped around the surface of three-dimensional metal oxides frame (C, N, S-CeO2) by oil bath heating method. The photocatalytic ability was determined by the degradation of organic pollutants under visible light. The photodegradation rate of tetracycline (TC) was nearly 80.1% within 30 min, and the apparent reaction rate constant (k) was 15.83 times higher than that of C, N, S-CeO2. Free radical capture experiments and electron spin resonance analysis showed that •O2-, •OH and 1O2 were the main active species. The structure of PDIs/C, N, S-CeO2 maintained stable after four cycles, meanwhile, anti-ion interference experiment illustrated that degradation efficiency was not affected by neutral ionic intensity. Further, the formation pathways of main degradation intermediates during the degradation process and the toxicity prediction of degradation intermediates were proposed. In addition, 10% PDIs/C, N, S-CeO2 could also efficiently degrade other organic pollutants (chlorotetracycline (CTC), ciprofloxacin (CIP), rhodamine B (RhB), methylene blue (MB)). The excellent photocatalytic activity of 10% PDIs/C, N, S-CeO2 was attributed to the matched energy band structure, establishment of multi-dimensional channels, more significant visible light assimilation performance and enhanced photothermal ability. This work provides a new perspective on the construction of n-n S-scheme heterojunction photocatalysts between self-assembled organic supramolecular materials and MOF-derived metal oxides.