Preparation of Non-Covalent BPTCD/g-CN Heterojunction Photocatalysts and Photodegradation of Organic Dyes Under Solar Irradiation.

In this study, the BPTCD/g-CN heterojunction photocatalyst was successfully prepared by the hydrothermal method. BPTCD (3,3',4,4'-benzophenone tetracarboxylic dianhydride) is immobilised on the surface of g-CN by non-covalent π-π stacking. The BPTCD/g-CN heterojunction photocatalyst is an all-organic photocatalyst with significantly improved photocatalytic performance compared with g-CN. BPTCD/g-CN-60% was able to effectively degrade MO solution (10 mg/L) to 99.9% and 82.8% in 60 min under full spectrum and visible light. The TOC measurement results indicate that MO can ultimately be decomposed into HO and CO through photocatalytic action. The photodegradation of methyl orange by BPTCD/g-CN composite materials under sunlight is mainly attributed to the successful construction of the heterojunction structure and its excellent π-π stacking effect. Superoxide radicals (O) were found to be the main active species, while OH and h played a secondary role. The synthesised BPTCD/g-CN also showed excellent stability in the activity of photodegradation of MO in wastewater, with the performance remaining above 90% after three cycles. The mechanism of the photocatalytic removal of MO dyes was also investigated by the trap agent experiments. Additionally, BPTCD/g-CN-60% demonstrated exceptional photodegradation performance in the degradation of methylene blue (MB). BPTCD/g-CN heterojunctions have great potential to degrade organic pollutants in wastewater under solar irradiation conditions.