Different hollow and spherical TiO2 morphologies have distinct activities for the photocatalytic inactivation of chemical and biological agents

Abstract

The inactivation of Escherichia coli and Qβ phage was examined following their photocatalytic treatment with TiO₂ hollows and spheres that had been prepared by electrospray, hydrothermal treatment, and calcination. The crystal structures of the hollows and spheres were assigned to TiO₂ anatase, and the surface areas of the hollows and spheres were determined to be 91 and 79 m² g⁻¹, respectively. Interestingly, TiO₂ spheres exhibited higher anti-pathogen performance than TiO₂ hollows, a difference we ascribe to the prevention of light multi-scattering by microorganisms covering the surfaces of the TiO₂ particles. The photocatalytic decomposition of dimethyl sulfoxide (DMSO) in the presence of TiO₂ hollows and spheres was examined in order to study the dependence of photocatalytic activity on TiO₂ morphology for the size scale of the reactants. TiO₂ hollows provided greater photocatalytic decomposition of DMSO than did TiO₂ spheres, in contrast to the pattern seen for pathogen inactivation. Fabrication of photocatalysts will need to vary depending on what substance (e.g., organic compound or biological agent) is being targeted for environmental remediation.