Curcumin Doped SiO<sub>2</sub>/TiO<sub>2</sub> Nanocomposites for Enhanced Photocatalytic Reduction of Cr (VI) under Visible Light
oleh: Zhiying Yan, Zijuan He, Mi Li, Lin Zhang, Yao Luo, Jiao He, Yongjuan Chen, Jiaqiang Wang
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2020-08-01 |
Deskripsi
In order to further improve the photocatalytic performance of the SiO<sub>2</sub>/TiO<sub>2</sub> composite under visible light irradiation, curcumin-doped SiO<sub>2</sub>/TiO<sub>2</sub> nanocomposites were synthesized via directly incorporating it into the structure of SiO<sub>2</sub>/TiO<sub>2</sub> during the synthesis using an inexpensive and readily available natural pigment (curcumin) as doping agent. The physicochemical properties of SiO<sub>2</sub>/TiO<sub>2</sub> nanocomposites were characterized in detail by X-ray diffraction, transmission electron microscopy, Fourier transform-infrared spectroscopy, N<sub>2</sub> adsorption–desorption isotherms, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. The results indicate that all SiO<sub>2</sub>/TiO<sub>2</sub> nanocomposites exhibited an anatase phase with a typical mesoporous structure. It was found that the dope of curcumin in the SiO<sub>2</sub>/TiO<sub>2</sub> composite could decrease the crystal size, slightly improve the specific surface areas, significantly enhance the visible light absorption, and effectively narrow the band gap energy from 3.04 to 10(eV). Compared with bare SiO<sub>2</sub>/TiO<sub>2</sub>, the curcumin-doped SiO<sub>2</sub>/TiO<sub>2</sub> resulted in enhanced photocatalytic reduction activity for Cr(VI) under visible light irradiation, and the CTS (12) sample with the appropriate content of curcumin of 12 wt % shows the photocatalytic yield reaching 100% within 2.5 hours, which is larger than CT (12) without silica. This could be attributed to the curcumin doping and the synergetic effects of SiO<sub>2</sub> and TiO<sub>2</sub> in SiO<sub>2</sub>/TiO<sub>2</sub> nanocomposites.