0D/3D coupling of g-C3N4 QDs/hierarchical macro-mesoporous CuO-SiO2 for high-efficiency norfloxacin removal in photo-Fenton-like processes.

Photo-Fenton process is an advanced oxidation technology, which is used to eliminate organic pollutants in environmental pollution. In this paper, g-C3N4 quantum dots incorporated hierarchical macro-mesoporous CuO-SiO2 (MM SC-QDs) composite was successfully fabricated by a dual-template method combined with polystyrene sphere (PS) crystal and copolymer F127. With the presence of H2O2, MM SC-QDs exhibited excellent degradation performance against the antibiotic pollutant norfloxacin (NOR) under visible-light assisted heterogeneous Fenton process at neutral condition, which was 27 times higher than that of the Bulk CuO-SiO2. Interconnected macropores, together with abundant mesopores effectively expand specific surface area and improve mass transfer. In addition, the g-C3N4 QDs served as the separation center for photogenerated charges, promoting the separation and migration of the charge carriers. Wherein, the long-lived photogenerated electrons were effectively separated and transferred to the surface of CuO-SiO2, which accelerated the reduction rate of Cu2+ to Cu+, enhancing the photo-Fenton-like catalytic activity. This stable, efficient, and environmentally friendly Cu-based heterogeneous photo-Fenton-like catalyst is expected to become an effective implementation in organic pollution removal. Meanwhile, this paper proves that Cu-based materials can activate H2O2 to generate singlet oxygen (1O2) for the degradation of organic pollutants. The transformation mechanism of 1O2 was clarified, which is helpful to better understand the Fenton-like reaction process of Cu-based materials.