Highly efficient photocatalytic performances of SnO2-deposited ZnS nanorods based on interfacial charge transfer

Abstract SnO 2 /ZnS nanocomposites of SnO 2 quantum dots (QDs)-deposited ZnS nanorods having highly enhanced photocatalytic activity and photostability have been fabricated via a facile two-step hydrazine-assisted hydrothermal process without involving any surface treatments. The photocatalytic activity of SnO 2 /ZnS nanocomposites with a Sn-to-Zn molar ratio (R Sn/Zn ) of 0.1 is 3 times higher than that of pristine ZnS nanorods and 17 times higher than that of commercial ZnS. The incorporation of SnO 2 QDs increases the photocatalytic efficiency of ZnS nanorods due to the following reasons: photogenerated charge carriers are readily separated owing to type II band configuration and direct contact at interfaces without having any linker molecules; active surface sites are increased to adsorb more dye molecules; the light absorption range is extended to the visible region, generating more charge carriers on the surfaces of heterojunction structures. The decay time, as well as the intensity, of the band-edge emission of SnO 2 /ZnS nanocomposites at 325 nm decreases progressively and rapidly with the increase of R Sn/Zn , indicating that fast electron transfer takes place from photoexcited ZnS nanorods to SnO 2 QDs. Thus, the higher photocatalytic degradation efficiencies of SnO 2 /ZnS nanocomposites are considered to result mainly from the increased separation rates of photogenerated charges. The photostability of SnO 2 /ZnS nanocomposites is also improved due to the protection and charge-separation effects of decorating SnO 2 QDs. Our prepared SnO 2 /ZnS nanocomposites are suggested to have great potential for photodegradation nanocatalysts in the field of waste-water treatment.