Green and facile microwave assisted synthesis of (metal-free) N-doped carbon quantum dots for catalytic applications

Industrialization today leads to a significant increase in the environmental pollution, with number of phenols, pesticides, paints, solvents and other organic pollutants with potentially carcinogenic effect in natural resources. Investigation of some new semiconductor materials and their photocatalytic properties for removal of pollutants is a challenging work. However, limited usage of photoactive materials still requires the testing of new materials with photoactive properties. The current work introduces the swift and easy approach for synthesis of (metal–free) N–doped carbon quantum dots in water using microwave reactor. Synthesis was performed from glucose water solution by heating in microwave reactor for only 1 min, at low temperature and applied microwave power. The synthesized N–doped carbon quantum dots show remarkable photocatalytic activity for removal of toxic organic dye (Rose Bengal) under visible light irradiation. Almost 93% of the dye degradation is achieved after only 30 min of radiation. The uninspected result, that the pH of the medium has a significant effect on the performance of the synthesized material in the presence of organic dye, indicates that dots show dual behavior. In the neutral and basic conditions, they have the ability to degrade organic dye, whereas, by shifting the medium pH into acidic medium, they form a stable conjugate with Rose Bengal.