Visible light photocatalytic activity of aromatic polyamide dendrimer/TiO2 composites functionalized with
Yonglin Lei1, Chi Zhang, Hong Lei
1State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, PR China. leiyonglin@163.com
Abstract:
A novel aromatic polyamide dendrimer-TiO2 hybrid photocatalyst functionalized with spirolactam-based molecular switch (RG-TiO2) was synthesized. The materials were characterized by FT-IR and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy, in comparison with reference materials (plain TiO2). The photocatalytic activity and photostability of RG-TiO2 were investigated based on the degradation of phenol under visible light irradiation. The results showed that the RG-TiO2 hybrid photocatalyst enhanced photocatalytic efficiency of photodegradation of phenol compared with the as-prepared plain TiO2 under visible light irradiation. More significantly, when the RG-TiO2 was acidified to pH 3, the RG-TiO2 was readily transformed from spirolactam form (OFF) to the ring-opened amide form (ON). And the photocatalytic stability of ring-opened RG-TiO2 (switch off form) was much lower than that of ring-closed RG-TiO2 (switch on form). The novel fabrication method of the TiO2 photocatalyst provides a valuable way for developing highly efficient and controllable photocatalysts by molecular switch.
