Preparation of porous C3N5 nanosheets by temperature modulation: Visible-light induced degradation characteristics and mechanism of microcystin-LR

Microcystin pollution of the environment is a prevalent problem that has gained considerable attention in sustainable development. Photocatalytic degradation is one of the most efficient ways to address this environmental issue. In this study, a porous C3N5 carbon nitride nanosheet (NCN) with high photocatalytic activity was prepared using 3-amino-1,2,4-triazole as the raw material by a simple and environmentally friendly stepwise pyrolysis technique. The morphology, microstructure, chemical composition, and optoelectronic properties of the materials were analyzed by characterization (SEM, TEM, XRD, FI-IR, XPS, UV–vis, PL, Etc.). The specific surface area and charge mobility of NCN were both increased by the porous structure. The specific surface area of NCN was 4.95 times greater than that of CN-650, and it has a narrower band gap and a broader visible absorption range. The degradation rate of microcystin-LR by NCN, driven by visible light, reached 99.99% at 45 min, and the degradation kinetic constant was 9.09 times that of its precursor. Singlet oxygen (1O2) plays the most crucial role in the photocatalytic degradation of MC-LR by NCN. In addition, possible degradation pathways were sought by studying the intermediates of the MC-LR photodegradation process. The NCN photocatalysts developed in this work provide a wide range of possibilities for photocatalyst design and the mechanistic analysis of photocatalytic degradation of microcystins.