Influence of TiO2 Support on Activity of Co3O4/TiO2 Photocatalysts for Visible-Light Water Oxidation

Co3O4-loaded TiO2 is a photocatalyst capable of oxidizing water into O-2 by absorbing an entire range of visible light (400 < lambda < 850 nm). In this work, the photocatalytic activity for water oxidation was investigated with respect to crystal phase, specific surface area, and surface morphology of TiO2 support. Results of photocatalytic reactions using six different TiO2 samples that possessed single-phase anatase or rutile structure indicated that the activity could be improved by applying a TiO2 support that had larger specific surface area, because it could accommodate larger amount of Co3O4 with minimal impact of undesirable aggregation. It was also suggested that when the specific surface area is similar, the activity is largely insensitive to crystal phase of TiO2, but is influenced by the surface morphology of TiO2, which can affect the dispersion of Co3O4.