BiVO 4 powders with unique particle architectures have been synthesized using ultrasonic spray pyrolysis (USP). Gases created from the evaporation of solvent and the decomposition of precursor materials shape the morphology of the particles as the solids are formed in the heated aerosol. The BiVO 4 powder was tested as oxygen evolving photocatalysts by monitoring the kinetics of O 2 formation from a AgNO 3 solution irradiated with λ > 400 nm light. USP prepared BiVO 4 was found to have significantly superior photocatalytic activity compared to commercial BiVO 4 and WO 3 , likely due to differences in particle morphology.

BiNbO 4 powders prepared by solid state reaction were tested for photocatalytic activity in methanol solutions under UV irradiation. When the material is tested without the presence of a Pt cocatalyst, photocatalytic activity for H 2 evolution is superior to that of TiO 2 . It was also found that BiNbO 4 photodegrades into metallic Bi and reduced Nb oxides after use; materials were characterized by SEM, XRD, and XPS. Adding Pt to the surface of the photocatalyst increases photocatalytic activity and importantly, helps to prevent photodegradation of the oxide material. With 1 wt % Pt loading, photodegradation is essentially absent.