Technical Research Center, Mazda Motor Corporation; 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima 730-8670 Japan
This report is the investigation results regarding the effect of Ce oxide (CeO2), Ce-Zr double oxide (Ce0.7Zr0.3O2), Ce-Pr double oxide (Ce0.9Pr0.1O2) and Pr oxide (Pr6O11) on the catalytic performances, structure and electronic state of Pt and Rh loaded on these oxides.
Based on the TPR evaluation results, it was found that the oxygen absorption-desorption performance of Pt-Rh/Ce0.9Pr0.1O2 and Pt-Rh/Pr6O11 are superior to Pt-Rh/CeO2 and Pt-Rh/Ce0.7Zr0.3O2.
Based on the XPS analysis results, it was found that the oxidation state of surface of Pt on Pt-Rh/Ce0.9Pr0.1O2 and Pt-Rh/Pr6O11 are higher than that on Pt-Rh/CeO2 and Pt-Rh/Ce0.7Zr0.3O2.
Based on XAFS analysis results, it was found that Rh on Pt-Rh/Ce0.9Pr0.1O2 and Pt-Rh/Pr6O11 are close to metallic in comparison with that on Pt-Rh/CeO2 and Pt-Rh/Ce0.7Zr0.3O2.
The state of precious metals and catalytic performances depend on the strong interaction between the precious metals and oxygen storage components (OSC).