Preparation of TiO2/SiO2 composite oxide and its photocatalytic degradation of rhodamine B

• DOI: 10.1007/s10934-015-0114-7
• Publication Date: 2015-12-21T07:52:00Z
• Authors: Zhi-Yuan Yang; Guang-Yu Shen; Yun-Peng He; Xiao-Xia Liu; Shui-Jin Yang
• Keywords: 02 engineering and technology; 0210 nano-technology; 01 natural sciences; 7. Clean energy; 0104 chemical sciences

The composite semiconductor photocatalyst TiO2/SiO2 was prepared by template-hydrothermal method using carbon spheres as the template. The structural and optical properties of TiO2/SiO2 were characterized by XRD, SEM, BET, UV–Vis DRS, TG-DTA, PL techniques. The formation of hydroxyl radical on the surface of TiO2/SiO2 was studied with terephthalic acid as the probe molecule, combined with fluorescence technique. The results showed that the specific surface area of TiO2/SiO2 composite was 327.9 m2/g, and the specific surface area of TiO2/SiO2 was larger than that of pure TiO2. Photocatalytic degradation of rhodamine B showed that TiO2/SiO2 composite oxide under visible light illumination 40 min, the degradation rate was 98.6 % and the degradation rate of pure TiO2 was only 11.9 %. The apparent first-order rate constant of TiO2/SiO2 was 33 times that of pure TiO2 and more than 6 times that of P25 when the molar ratio of Ti to Si was 1:1 under visible light irradiation. Moreover, it’s also as much as 5 times that of pure TiO2 and is more than 1 times that of P25 under UV light irradiation 25 min. Based on the experimental results, ·O2 − and h+ were suggested to be the major active species which was responsible for the degradation reaction. The increased photocatalytic activity of TiO2/SiO2 may be mainly attributed to effectively suppressing the recombination of hole/electron pairs. After the photocatalyst TiO2/SiO2 was reused 5 times, the degradation rate of rhodamine B could reach 89.2 % under visible light irradiation. Moreover, The composite semiconductor photocatalyst TiO2/SiO2 was selective towards the degradation of rhodamine B.