Efficient photocatalytic-fenton oxidation performance of Fe3+/g-C3N4/NCDs nanorods: Structure-activity relationship of photocatalytic degradation of water pollutants

In this article, the two-dimensional N-doped carbon quantum dot (NCDs) loaded g-C3N4 materials were prepared firstly by microwave and hydrothermal methods (2D g-C3N4/NCDs). The results show that the doping of NCDs improves the charge distribution in the conventional g-C3N4 material and provides more active sites. The catalytic activity of 2D g-C3N4/NCDs material with 2% doping was 3.4 times higher than that of g-C3N4 material. Next, 3D Fe3+/g-C3N4/NCDs materials were obtained by using Fe3+ ions to induce self-assembly of 2D g-C3N4/NCDs materials under the action of ultrasound. The transformation of the material from 2D to 3D enhances its electron transport capability and visible response range and reduces the band gap value. Meanwhile, the Fenton oxidation effect of Fe ions combined with the photocatalytic effect of the material produced a special photo-Fenton oxidation, which enhanced the oxidation ability of the composite. Thus, 3D Fe3+/g-C3N4/NCDs materials can degrade a variety of water pollutants (Such as Methyl orange, Rhoda mine B, alizarin red, acidic fuchsine, tetracycline hydrochloride and aureomycin hydrochloride) under light without the addition of additional H2O2, exhibiting excellent catalytic activity (18.75 times of conventional g-C3N4). In addition, the 3D Fe3+/g-C3N4/NCDs can activate water efficiently to produce active species •O2− and •OH in situ under visible light, which improved the photocatalytic activity of Fenton-like photocatalyst 3D Fe3+/g-C3N4/NCDs. The research in this paper improves the photocatalytic activity of g-C3N4 materials in two dimensions, microscopic electronic structure and macroscopic stereo structure, which will provide new ideas for the application of AOPs in clean production.