Sonohydrothermal Synthesis of Nanostructured (Ce,Zr)O2 Mixed Oxides with Enhanced Catalytic Performance

We report for the first time evidence of sonochemical activity under hydrothermal conditions. Sonolysis of H2O and D2O using 20 kHz power ultrasound at 200 °C and 13 bar in the presence of argon yields H2 and D2 respectively. Formation of hydrogen peroxide is not observed because of its thermal instability. The simultaneous sonohydrothermal treatment was used for the preparation of Ce0.5Zr0.5O2 nanocrystalline mixed oxide with external mesoporous surface area higher than that of similar material prepared by ultrasonically assisted coprecipitation followed by hydrothermal treatment. The obtained mixed oxide loaded with 1.5 wt % of platinum exhibits high activity and stability in catalytic wet air oxidation of formic acid at low temperature.