Promoter effect of niobia on Pt/Al2O3 catalysts.

Q4 Chemical Engineering

分子催化 Pub Date : 1994-08-30 DOI:10.1016/0304-5102(94)00073-5

L. Guczi, T. Hoffer, Z. Zsoldos

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引用次数: 7

Abstract

The effect of chlorine using precursors like H₂PtCl₆ (0.55,2 and 10 wt.% Pt) and Pt(NH₃)₄(NO₃)₂ (2 wt.% Pt) and of the Nb₂O₅ loading on the structure of Pt/Al₂O₃ and its catalytic activity in methanol/deuterium exchange has been investigated. In presence of niobia the BET surface of the support increases but niobia itself remains amorphous and its presence in increasing quantities results in the easier reduction of both chlorine-containing and chlorine-free Pt samples measured by TPR. XPS provides evidence for the effect of chlorine and niobia on the reduction of Pt. After reduction Nb₂O₅ is converted into NbO_x species which may migrate on top of the Pt particles measured by XRD, CO chemisorption and O/H titration. The increased perimeter of the Pt/NbO_x/Al₂O₃ interface raises the deuterium availability across this interface, which in turn, gives rise to the interaction of methyl groups in the anchored species with Pt for multiple exchange as was assumed in Part I.

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铌对Pt/Al2O3催化剂的促进作用。

研究了以H2PtCl6(0.55、2和10 wt.% Pt)和Pt(NH3)4(NO3)2 (2 wt.% Pt)为前驱体的氯和Nb2O5负载对Pt/Al2O3结构及其在甲醇/氘交换中的催化活性的影响。在铌的存在下，载体的BET表面增加，但铌本身保持无定形，其数量的增加导致TPR测量的含氯和无氯Pt样品更容易还原。通过XRD、CO化学吸附和O/H滴定法测定，Nb2O5在还原后转化为NbOx, NbOx可以迁移到Pt颗粒的顶部。Pt/NbOx/Al2O3界面周长的增加提高了该界面上氘的可用性，这反过来又引起了锚定物质中甲基与Pt的相互作用，如第一部分所假设的那样进行多次交换。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

分子催化 Chemical Engineering-Catalysis

CiteScore

1.50

自引率

0.00%

发文量

2959

期刊介绍： Journal of Molecular Catalysis (China) is a bimonthly journal, founded in 1987. It is a bimonthly journal, founded in 1987, sponsored by Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, under the supervision of Chinese Academy of Sciences, and published by Science Publishing House, which is a scholarly journal openly circulated both at home and abroad. The journal mainly reports the latest progress and research results on molecular catalysis. It contains academic papers, research briefs, research reports and progress reviews. The content focuses on coordination catalysis, enzyme catalysis, light-ribbed catalysis, stereochemistry in catalysis, catalytic reaction mechanism and kinetics, the study of catalyst surface states and the application of quantum chemistry in catalysis. We also provide contributions on the activation, deactivation and regeneration of homogeneous catalysts, solidified homogeneous catalysts and solidified enzyme catalysts in industrial catalytic processes, as well as on the optimisation and characterisation of catalysts for new catalytic processes. The main target readers are scientists and postgraduates working in catalysis in research institutes, industrial and mining enterprises, as well as teachers and students of chemistry and chemical engineering departments in colleges and universities. Contributions from related professionals are welcome.