(a) Reduction performance of the removal of MB molecules from the water solution(80 mg/L, 2 mL) in the presence of 0.36-mg CdS core–shell nanomaterials and 0.36-mg CdS nanocages, respectively. (b) and (c) The adsorption behaviors of MB solution (90 mg/L, 80 mL) via different reaction times. The required CdS nanocages is 0.36 mg. (d) The FTIR spectra of the as-prepared CdS nanocages before and after adsorbing MB molecules.