The ultrasonic synthesis of nanostructured metal oxide catalysts

This paper describes the synthesis of a wide range of metal oxide and supported metal catalysts to determine whether ultrasonic treatment during precipitation affords any advantages for the preparation of nanostructured materials compared to identical syntheses by classical precipitation. The investigation concentrated on a determination of ultrasound effects during synthesis on reducing and controlling grain sizes, improving phase purities of complex metal oxides, improving the degree of alloy formation for supported bimetallic catalysts, and the capability to systematically vary and control grain sizes of the metallic particles. Based on current experimental results, it seems that the general effect of ultrasound on these syntheses was relatively minor, and in only a few cases consequential. In some cases, such as ceria and titania, the effect was more dramatic; however, the degree of variability of grain sizes and phase purity were less than expectations.