{"title":"Promoter effect of niobia on Pt/Al2O3 catalysts.","authors":"L. Guczi, T. Hoffer, Z. Zsoldos","doi":"10.1016/0304-5102(94)00073-5","DOIUrl":null,"url":null,"abstract":"<div><p>The effect of chlorine using precursors like H<sub>2</sub>PtCl<sub>6</sub> (0.55,2 and 10 wt.% Pt) and Pt(NH<sub>3</sub>)<sub>4</sub>(NO<sub>3</sub>)<sub>2</sub> (2 wt.% Pt) and of the Nb<sub>2</sub>O<sub>5</sub> loading on the structure of Pt/Al<sub>2</sub>O<sub>3</sub> 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 Nb<sub>2</sub>O<sub>5</sub> is converted into NbO<sub><em>x</em></sub> 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<sub><em>x</em></sub>/Al<sub>2</sub>O<sub>3</sub> 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.</p></div>","PeriodicalId":16567,"journal":{"name":"分子催化","volume":"92 2","pages":"Pages 167-186"},"PeriodicalIF":0.0000,"publicationDate":"1994-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)00073-5","citationCount":"7","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"分子催化","FirstCategoryId":"1089","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0304510294000735","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"Chemical Engineering","Score":null,"Total":0}
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 NbOx 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/NbOx/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.
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.
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