Photocatalytic CO2 Reduction and Thermal Properties of Alumina/Silica Coated TiO2 Nanoparticles

Abstract

In this study, the surface of TiO2 was coated with SiO2 and Al2O3 layers by sol-gel and chemical deposition methods. Firstly, the TiCl4 was magnetically stirred for 1 h in deionized water, and then the NaOH solution was drop wised to the solution and stirred 2h. Finally, the obtained TiO2 was washed, filtered, and dried in a vacuum oven. The surface of TiO2 was coated with SiO2 and Al2O3 layers subsequently by chemical deposition methods. The morphological, thermal, and crystal properties of products were determined via SEM, TGA, and XRD machines. The X-ray diffraction peaks displayed that the TiO2 nanoparticles were synthesized without any extra peaks. Moreover, the SiO2 and Al2O3 coated TiO2 particles contain extra SiO2 and Al2O3 peaks, indicating that the surface of TiO2 was coated via SiO2 and Al2O3. The SEM results displayed that TiO2 and SiO2 and Al2O3 coated TiO2 were spherical in shape, and the size distribution was found to be around 20-50 nm and 200-300 nm, respectively. The photocatalytic and UV–vis analyses were used to determine the CO2 reduction and optical properties of particles. The results showed that the absorption peaks were broad to longer wavelength with a coating of SiO2 and Al2O3. The CO2 reduction performance of TiO2 has been enhanced via coating SiO2 and Al2O3 layer.