One arrow two hawk approach for simultaneous detection and photoreduction of toxic hexavalent chromium by N, S-co-doped carbon dots

The pervasive presence of hexavalent chromium (Cr(VI)) ions in water, coupled with their highly toxic and carcinogenic nature, poses a serious threat to aquatic ecosystems and human well-being. Hence, to mitigate this concern, blue luminescent carbon dots (CG-CDs) have been synthesized using readily available low-cost precursors, namely citric acid and glutathione, which exhibited remarkable capabilities for both sensing as well as photoreduction of toxic Cr(VI). Their selectivity and sensitivity are truly remarkable, with a detection limit as low as 78 nM showing no significant interference with other ions. In addition to its application in fluorometric detection, CG-CDs also showed impressive photocatalytic properties for the reduction of hazardous Cr(VI) to less toxic Cr(III) ions when exposed to sunlight, achieving ∼ 99% conversion of 25 ppm Cr(VI) within a mere 30 min at pH 4 using 1 mg/mL of CG-CDs. Additionally, the effective sensing and reduction ability of CG-CDs towards Cr(VI) in real water samples makes them versatile material for detecting and photoreducing Cr(VI) in aqueous environments.