Bio-waste derived S, N-enriched carbon quantum dots: an in-depth analysis of various factors affecting photocatalysis

Carbon-based nanomaterials are becoming increasingly prevalent due to their high degradation rates for various aquatic contaminants. However, their expensive and complex synthesis poses a major challenge. One of the most efficient and easy methods to degrade dyes is by the use of carbon quantum dots (CQDs). This research focuses on the degradation of an aquatic pollutant by deriving CQDs from green sources, as plant part-based CQDs possess the potential to degrade aquatic contaminants. In this study, we first examine the use of Dalbergia sissoo as a method for producing bare or unmodified carbon quantum dots (UCQDs) and S and N co-enriched carbon quantum dots (S, N-CQDs) through a straightforward, rapid, and single-step microwave process. EDX, FTIR, FESEM, XRD, and UV-Visible spectra were utilized to characterize CQDs. The zeta potential of as-synthesized CQDs was also measured. The photocatalytic activity of CQDs was studied by degrading a cationic dye known as Malachite Green (MG) dye, along with optimization of various factors, notably pH, dye concentration, and CQD volume, which were also tuned. S, N-CQDs reported outstanding photocatalytic capacity (95.12%) toward 15 ppm MG dye in bright sunlight at a pH of 9, employing 1 ml of photocatalyst. These CQDs emerged as a promising photocatalyst due to their easy synthesis and remarkable photocatalytic efficiency.