Multifunctional CdS Nanoparticle-Decorated CeO₂ as Efficient Visible Light Photocatalysts and Toxic Cr(VI) Sensors

Several one-dimensional and three-dimensional CdS@CeO₂ nanocomposites were synthesized by a solvothermal route. A nanoflower-shaped CdS@CeO₂ nanocomposite (CdS-NF@CeO₂) was selected as the model catalyst after various characterizations. It was, then, employed directly as a luminescent sensor for Cr(VI) detection in an aqueous medium. A good linear quenching was observed in the range of 0-0.5 μM with a detection limit of 0.04 μM. The quantum yield of the catalyst was found to be 73%. Moreover, our catalyst is highly selective toward Cr(VI) and can be applied as an efficient sensor for real water analysis. The efficiency of the catalyst was also tested in controlling the photocatalytic activity for oxidation of benzylamine to N-benzylidenebenzylamine under a domestic LED bulb with molecular O₂ as a sole, green oxidant. Conversion (>99.9%) and selectivity as high as 100% were observed for the CdS-NF@CeO₂ photocatalyst. These results show the potential applications of CdS-NF@CeO₂ nanocomposites as an efficient photocatalyst for organic transformation and environmental remediation.