Fabrication and characterization of g-C3N4 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-C3N4 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 i.e. concentration of dye, time, catalyst dose, and pH under UV irradiation and dark conditions. The results evidenced that Cu-g-C3N4 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-C3N4 is a highly stable catalyst. Thus, Cu-g-C3N4 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.

Photocatalytic degradation of imidacloprid using Ag2O/CuO composites.

Imidacloprid is one of the most commonly used neonicotinoid pesticides that has been identified as a neurotoxin for various non-target organisms. It binds to the central nervous system of organisms, causing paralysis and eventually death. Thus, it is imperative to treat waterwaters contaminated with imidacloprid using an efficient and cost effective method. The present study presents Ag2O/CuO composites as excellent catalysts for the photocatalytic degradation of imidacloprid. The Ag2O/CuO composites were prepared in different compositions by adopting the co-precipitation method and used as a catalyst for the degradation of imidacloprid. The degradation process was monitored using UV-vis spectroscopy. The composition, structure, and morphologies of the composites were determined by FT-IR, XRD, TGA, and SEM analyses. The effect of different parameters i.e time, concentration of pesticide, concentration of catalyst, pH, and temperature on the degradation was studied under UV irradiation and dark conditions. The results of the study evidenced the 92.3% degradation of imidacloprid in only 180 minutes, which was 19.25 hours under natural conditions. The degradation followed first-order kinetics, with the half life of the pesticide being 3.7 hours. Thus, the Ag2O/CuO composite was an excellent cost-effective catalyst. The non-toxic nature of the material adds further benefits to its use. The stability of the catalyst and its reusability for consecutive cycles make it more cost effective. The use of this material may help to ensure an immidacloprid free environment with minimal use of resources. Moreover, the potential of this material to degrade other environmental pollutants may also be explored.