Investigation of a traditional catalyst by contemporary methods: Parallel electron spectroscopic and catalytic studies on Pt black

SURFACE SCIENCE

卷:603

Article

Paal, Zoltan^1,2  Schloegl, Robert² 

[1] Hungarian Acad Sci, Inst Isotopes, H-1525 Budapest, Hungary

[2] Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany

关键词: Electron spectroscopy;    XPS;    UPS;    Pt catalyst;    Hexane reactions;    Catalyst carbonization;   

DOI  :  10.1016/j.susc.2008.08.044

来源: Elsevier

【 摘 要 】

Results of electron spectroscopy (XPS and UPS) of platinum black catalyst measured in various states of the catalyst have been summarized. XPS showed up to almost 50% carbon and up to 20% oxygen on a sample stored in air. These, however, had almost no influence on the chemical state of Pt, except for the appearance of minor surface oxide. A Pt purity of similar to 90% could be reached by regeneration with O(2) and H(2). The C 1s peak contained several components from individual C atoms to graphitic and polymeric hydrocarbon layers. Thus, the active catalyst was not clean Pt but metallic Pt; the impurities exerting little influence on catalytic activity. Regeneration and deactivation led also to slight structural rearrangement, as detected by XRD. Intentional deactivation with hydrocarbon-hydrogen mixtures was monitored by XPS, UPS and catalytic tests. Correlation was found between catalytic activity and selectivity in hexane reaction and the amount - and also the chemical state - of carbon accumulated during deactivating runs. A short summary of electron spectroscopy of supported Pt catalysts is also given. The main underlying idea regards solid catalyst and reactants as a dynamic system, including also solid-state changes of the former. (C) 2009 Published by Elsevier B.V.

【 授权许可】

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