Microstru cture and oxygen storage capacity of Sr-modified Pt/CeO2 –ZrO2catalysts |
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作者姓名: | Rui Ran Jun Fan Duan Weng |
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作者单位: | State Key Lab of New Ceramic and Fine Processing, Department of Materials Science and Engineering,Tsinghua University, Beijing 100084, China;The Administrative Centre for China’s Agenda 21, Beijing 100038, China;State Key Lab of New Ceramic and Fine Processing, Department of Materials Science and Engineering,Tsinghua University, Beijing 100084, China |
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摘 要: | Strontium was introduced into CeO2–ZrO2 mixed oxides (CZ) by doping and impreg-nation metho ds, and then Pt was impregnated on the Sr-modifie d CZ to obtain the catalysts. X-ray diffraction (XRD), X-photon spectra (XPS), high-resolution transmission electronic microscopy (HRTEM) and H2 temperature programmed reduction (TPR) were carried out to characterize the micro-structure and reducibility of catalysts. The oxygen storage capacity (OSC) was evaluated with CO serving as probe gas. The results showed that the incorporation of Sr2+ in the lattice of CZ could promote the OSC properties by increasing the structure defects and enhancing the diffusion rate of oxygen from bulk to surface. For the Sr-impregnated sample, the strong metal–support interaction (SMSI) between Pt and CZ was interrupted, since Sr covered parti al surface Ce species. Such interruption retarded the back-spillover effect occurring at the Pt/Ce interface at low temperature, resulting in the loss of OSC. Meanwhile, it was found that a part of impregnated Sr2+ could partially diffuse from the surface to the inner atomic layers of CZ and partially incorporated in the lattice during the calcination. The OSC performance of Sr-impregnated sample therefore climbed remarkably with the rise of temperature.
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关 键 词: | CeO2 –ZrO2 mixed oxides Strontium Platinum Micro-structure OSC |
收稿时间: | 2011-10-13 |
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