CdS quantum dots (QDs) have emerged as the promising nanomaterial for various applications. This study reported bi-functional usage of aqueous starch capped CdS QDs as heavy metal-ion sensor for selective detection of Hg2+ and Cu2+ in aqueous medium as well as sunlight driven photocatalyst for degradation of organic dyes. CdS QDs exhibited colorimetric, spectroscopic, and compositional change with Hg2+ and Cu2+ via cation exchange reaction (CER). The CER of yellow color CdS QDs solution with Hg2+ showed rapid colour change to orange, red and white with composition Cd1-xSHgxS, HgS/CdS, and mixture of HgS and Hg sol, respectively whereas, CER of CdS QDs with Cu2+ resulted in pale brown, brown and greenish brown with composition Cd1-xCuxS, CuxS/CdS and Cu2-xS, respectively. Further, CdS QDs displayed excellent sunlight driven photocatalytic degradation of cationic, anionic and hair dye with good efficiency, reusability, and stability.
Read full abstract