Ag-Ag2S quantum-dots modified TiO2 nanorod arrays with enhanced photoelectrochemical and photocatalytic properties

In this paper, highly ordered titanium dioxide nanorod (TNR) arrays decorated with Ag-Ag 2 S quantum-dots (QDs) were synthesized on FTO substrate through hydrothermal treatment and in-situ vulcanization . The content of Ag 2 S QDs on Ag/TNR was controlled by changing the immersion time of Ag/TNR in the N-N-dimethyl formamide (DMF) solution containing dissolved sulfur element. The morphology, structure, composition and optical, photoelectric and photocatalytic properties of QDs/TNR arrays were studied in detail. In the visible range, the QDs/TNR array with a soaking time of 12 h exhibits the maximal photocurrent density (0.082 mA/cm 2 ) and photodegradation rate (62.2%), which is 5.5 and 1.85 times higher than that of pure TNR. The improvement of these properties could be attributed to synergy effect between Ag and Ag 2 S materials. That is, Ag QDs can stably capture and transmit photo-generated electrons from the TNR surface, whereas the Ag 2 S promoter is regarded as the interface active sites to enhance photocatalytic reactions. Therefore, the synergistic effect of Ag-Ag 2 S can significantly enhance the photoelectrochemical and photocatalytic properties of the TNR arrays.