Porous silica/TiO2 Nanocomposite for Collective Adsorption and Degradation Functionalities

Abstract

The performance of photocatalytic oxidation of volatile organic compounds (VOCs) generally depends on two properties: VOCs adsorption abilities as well as the degradation functionalities. In this work, a hybrid system of silicon dioxide (SiO2) and titanium dioxide (TiO2) was synthesized for enhanced degradation functionalities. The reasons for high demand of porous silica in the applications are attributed to the low cost, high surface area and the feasibility of obtaining various pore sizes. A simple aqueous-phase method was used to synthesize different structures of porous silica for VOC adsorption capabilities. Porous SiO2 rods of the highest surface area (1238 m2g-1) was chosen to incorporate with the TiO2 sheets for enhanced degradation. Hydrothermal TiO2 growth on SiO2 was optimized by varying the amount of precursors used. The synthesized materials were characterized with scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and photocatalytic performance for VOC degradation under UV-LED illumination. The optimized SiO2rods@TiO2 sample showed enhancement of degrading up to 60 % in 120 min of degradation. Furthermore, CuO acts as an effective co-catalyst to enhance charge separation and the degradation performance was improved by loading the SiO2rods@TiO2 sample with CuO. A loading amount of 5% was found to be the optimum for enhanced degradation performance.