Fabrication and characterization of g-CN supported Cu-single atom catalysts for the photocatalytic degradation of dyes.

Methylene blue and Congo red are widely used organic dyes in biomedical laboratories and textile industries. The abundant use of these dyes has led to their emission in wastewaters, which causes major health hazards to exposed populations. Therefore, it is necessary to properly treat the dye effluents before being discharged into the water bodies. The present study presents Cu-g-CN as an efficient and cost-effective catalyst for the photocatalytic degradation of these dyes. The single-atom catalyst was prepared by a simple co-precipitation method and the composition, structure, morphologies, and electronic state were determined by FT-IR SEM, XRD, XPS, PL, and TGA analyses. The photocatalytic activity of the catalyst was studied by optimizing various parameters concentration of dye, time, catalyst dose, and pH under UV irradiation and dark conditions. The results evidenced that Cu-g-CN is an excellent catalyst as it achieved 100% degradation of the methylene blue and Congo red dyes in only 5 and 30 minutes respectively. The kinetics of photocatalytic degradation revealed that the half-life of methylene blue and Congo red was reduced significantly. The stability of the catalyst was determined by using it for five consecutive cycles and the results proved that Cu-g-CN is a highly stable catalyst. Thus, Cu-g-CN proved itself to be a highly active, stable, and cost-effective catalyst for the degradation of dyes with minimum resources. This material is also believed to have great potential to degrade other environmental pollutants too.