Facile synthesis of Ag/CdS composites with improved photocatalytic performance

Abstract

Ag/CdS composites were prepared by low-temperature solid-phase chemical reaction with the aid of sodium borohydride, and the effects of Ag content and surfactant sodium dodecyl sulfate on the composition, structure and catalytic activity of the composites were investigated. The photocatalytic results show that the composites AGCS-0.5 displays the highest photocatalytic performance when the mass percentage of Ag to CdS is 0.5. After introducing surfactant sodium dodecyl sulfate, the catalytic activity of the composites is also significantly improved. It can be attributed to the following aspects, on the one hand, introduction of Ag can enhance the light absorption ability of Ag/CdS composites, which leads to more carriers participating in the catalytic reaction. On the one hand, Ag is closely combined with CdS in the composites, which is beneficial to the rapid separation of photogenerated carriers. Furthermore, the surfactant sodium dodecyl sulfate enhances the synergistic effect between Ag and CdS, reduces the recombination probability of photogenerated electron-holes, and thus enhances the photocatalytic activity. Combined with UV–vis absorption spectroscopy, photocurrent, fluorescence spectroscopy and active species capture agents, a possible photocatalytic mechanism was proposed.