Chitosan hydrogel films as a template for mild biosynthesis of CdS quantum dots with highly efficient photocatalytic activity

► CdS quantum dots were prepared in situ in crosslinked chitosan hydrogel films. ► CdS QDs exhibited a good photocatalytic activity. ► Dye photodegradation followed pseudo-first-order kinetics. ► CdS QDs/chitosan composite films were suitable for potential application.