Structure Analysis of CeO2-ZrO2 Mixed Oxides as Oxygen Storage Promoters in Automotive Catalysts
نویسندگان
چکیده
Oxygen storage/release (OSC) capacity is an important feature common to all three-way catalysts that enables them to efficiently remove harmful compounds such as hydrocarbons, CO and NOx in automotive exhaust gases. In this report, three types of CeO2-ZrO2 (Ce:Zr = 1:1 molar ratio) compounds with different OSC were characterized by means of XRD (X-ray diffraction) and XAFS (X-ray absorption fine structure). The relationship between the compounds’ OSC and molecular structure was investigated by quantitative EXAFS curve-fitting analysis. Enhancing the homogeneity of the Ce and Zr atoms in the CeO2-ZrO2 solid solution increased OSC performance, and greatly changed the local oxygen environment around Ce and Zr. The improvement in OSC was attributed to the increase in homogeneity of the CeO2-ZrO2 solid solution and to the change in the oxygen environment.
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