Qing Chang

TiO2 nanotube array with “multi-layer” walled structure and its vulnerability to water

“Multi-layer” walled TiO2 nanotube array has been prepared by anodization with post-treatment of ethanol. Two post-treatment methods, which were ethanol and water treatment respectively, exerted a marked and different effect on the structure of nanotube. With ethanol immersion, the “multi-layer” walled nanotube can be obtained, while water treatment cannot produce the “multi-layer” walled structure. The main reason could be the uptake of carbon and fluoride during anodization process. Compared with “single-layer” walled TiO2 nanotube, “multi-layer” walled TiO2 nanotube demonstrated higher photocatalytic activity.

Carbon-Dot-Based Heterojunction for Engineering Band-Edge Position and Photocatalytic Performance

A photocatalytic reaction is always governed by energy band configuration of the catalyst, but its modulation is challenging. Here, the adjustment of band-edge positions of Ag3 PO4 through fluorescent carbon dots is reported for the first time. Both Ag3 PO4 and carbon dots which keep the similar sizes constitute a heterojunction. Such heterostructure not only promotes visible light absorption, photogenerated charge separation, and transfer, but it also transforms photocatalytic activity of Ag3 PO4 from photooxidation to photoreduction due to the huge changes of band-edge positions. In addition, the heterojunction structure of carbon dots and Ag3 PO4 exhibits unique temperature-responsive photocatalytic activities and higher photocatalytic stability than the pure Ag3 PO4 . According to the contrast experiments and related characterizations, the possible mechanism of photocatalytic reaction is proposed. Therefore, this work offers an alternative route for adjusting energy band positions or tuning photocatalytic performance as well as for preparing novel carbon-dot-based heterostructure.