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Structure and methanol activation: niobia promoted Pt/Al2O3 catalysts

✍ Scribed by T. Hoffer; S. Dobos; L. Guczi


Publisher
Elsevier Science
Year
1993
Tongue
English
Weight
870 KB
Volume
16
Category
Article
ISSN
0920-5861

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✦ Synopsis


Distinction between geometric and ligand effects has been studied by the infrared study of CO chemisorption on four catalyst samples modified by niobia. According to earlier studies the metal-support interface plays a crucial role in the CH OH + D reaction. Platinum and niobia content, oxidative-reductive treatment and chlort e content .d l! as a great influence of the niobia decorating Pt surface. High temperature reduction does not effect niobia-free sample, while niobia addition decreases the bridged/linear ratio of the adsorbed CO, especially in the SMSI state. Simultan~usly the peak positions are shifting towards higher frequencies. Both geometric effect of decoration and ligand effect are observed.

The observed effect has been further supported by XRD data for the platinum crystallite sizes and a quantitative parameter for the characterization of SMSI is proposed.


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