On the sintering of platinum on alumina model catalyst
作者： YF Chu , E Ruckenstein
DOI: 10.1016/0021-9517(78)90217-8
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摘要: A model catalyst suitable for examination in the transmission electron microscope is used to study sintering of Pt crystallites supported on alumina. The consists a thin layer γ-Al2O3 upon which deposited. samples are subjected heating various chemical atmospheres lengths time and temperatures. change size, shape, position each crystallite followed by examining same region after step treatment. Crystallite migration identified as cause sintering. Evidence size larger than about 10 nm over large distances presented. degree mobility depends conditions. Increase temperature, periodic oxidation reduction, reaction with substrate, burning off coke accumulated surface all enhance migration. Phase transformation occurring alumina substrate also associated severe crystallites. Heating pure oxygen or wet N2 does not promote appreciably. Significant occurs during H2.
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