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記事情報

PDF	PDF1.2 MB(閲覧回数：2040回)
巻・号	10巻1号	ページ	2
記事分類・特集	原報
題目(和文)	貴金属合金触媒
著者	吉田和夫
要旨(英文)	The catalytic activity of Group 8 metals has been ascribed to the electronic structure of the metal, especially to that of the d-band. Many investigations of the Ni-Cu alloy catalyst, including Dowden's first successful attempt, have not, however, been consistent.Alloys composed of the Group 8 noble metals, such as Ru-Pt, Rh-Pt and Rh-Pd, were recently found to be quite effective in catalysis; their catalytic activities changed, in most cases, continuously with the change in the alloy composition.The present paper gives the results of an investigation of supported Rh-Pt alloy catalysts. The supported Rh-Pt alloy catalysts, prepared by the reduction of these metal salts in an qaueous solution, proved very active in hydrogenating the nuclei of aromatic compounds. By X-ray diffraction it was confirmed that the homogeneous Rh-Pt alloy was formed on the catalyst support.The activity per unit of surface area was shown as a function of the alloy composition, with a maximum at a certain composition between 20 and 40 atomic % of Rh. The dependence of the catalytic activity on the alloy composition was found to be quite similar to that of the atomic susceptibility of the alloy, which was measured at room temperature by the use of a Faraday balance.This finding leads to the conclusion that the activity of the alloy catalyst is closely related to the number of unpaired d-electrons present in the metal.The gas adsorpition (N2 and CO) method was used to study the state of the dispersion of the meatl on the carrier; it was concluded that the catalyst was composed of several atomic layer islands of the metal on the carrier surface, a conclusion which is in good agreement with the X-ray results.The role played by adsorbed oxygen in the catalytic action was investigated and discussed in connection with the vacancy in the d-band of the metal.The catalytic activities of other noble metal alloys were then discussed in the same manner.The success in relating the catalytic activity to the electronic property of the metal results from the nature of the alloy ; that is, Rh and Pt had the same crystal structure, and almost the same lattice constant, and a complete homogeneous alloy was formed throughout the entire range of composition. In this case the electronic property of the surface might be expected to be the same as that of the bulk.
発行年月日	2016-12-01	公開日	2016-12-01
パーマリンク	https://catsj.jp/jnl/pageview?articlecd=1001000200g