Microwave-assisted solid-phase synthesis of N-doped carbon dots for the catalytic reduction of malachite green and crystal violet dyes
摘要
In this study, we present a simple and efficient microwave-assisted solid-phase synthesis of nitrogen-doped carbon dots (NCDs) using citric acid and 2-aminobenzimidazole as precursors. The synthesis conditions were systematically optimized, and the resulting NCDs were extensively characterized for their physicochemical and optical properties. Transmission electron microscopy revealed that the NCDs are spherical in shape with an average diameter of 5 ± 1 nm. X-ray photoelectron spectroscopy confirmed successful nitrogen incorporation into the carbon framework. The NCDs exhibited bright blue fluorescence under 320 nm UV Light, a high quantum yield of 12.6%, excellent water dispersibility, and strong photostability under varying environmental conditions. The catalytic performance of the NCDs was evaluated through NaBH4-assisted reduction of malachite green (MG) and crystal violet (CV) dyes. In both cases, over 90% degradation was achieved within 12 min. The reaction kinetics followed a pseudo-first order model, with rate constants of 0.070 ± 0.01 min−1 for MG and 0.139 ± 0.02 min−1 for CV. These results highlight the potential of the synthesized NCDs as effective and eco-friendly catalysts for the rapid removal of dye pollutants in wastewater treatment applications.