Comparison of Aqueous Photoreactions with TiO2 in its Hydrosol Solution and Powdery Suspension for Light Utilization

Abstract

In aqueous photoreaction systems, the existence of gradient light intensity throughout the reaction solution is one of the important restrictions to the efficiency of the overall photoreaction, which highly relies on the optical properties of the catalyst such as light absorption and scattering effects, the particle size of the catalyst, and the degree of agglomeration in its slurry. In this study, both synthesized TiO2 hydrosol and commercial TiO2 powder, Degussa TiO2 P25, were used as catalysts for comparison, in which their particulate and optical properties in aqueous solution/suspension were investigated. The characteristic results showed that the TiO2 hydrosol had smaller crystal sizes and particle sizes, but a lower degree of crystallinity compared to the P25 powder. As TiO2 hydrosol solution had the much lower light extinction coefficient than P25 suspension, the attenuation of light intensity gradient in the reaction solution containing more transparent TiO2 hydrosol was greatly eliminated. Howev...