Influence of the strong metal-support interaction on the CO chemisorption at a Pt/SiO2 catalyst

被引:37
作者
Hippe, C [1 ]
Lamber, R [1 ]
SchulzEkloff, G [1 ]
Schubert, U [1 ]
机构
[1] TECH UNIV VIENNA, INST ANORGAN CHEM, A-1060 VIENNA, AUSTRIA
关键词
silica-supported platinum; sol-gel processing; strong metal-support interaction; FTIR-spectroscopy; electron microscopy; electron diffraction;
D O I
10.1023/A:1018919412751
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Pt/SiO2 catalysts prepared by sol-gel processing were studied by transmission electron microscopy, electron diffraction, high-resolution electron microscopy and Fourier-transform infrared spectroscopy. The samples exhibit uniform dispersion of the metal phase with narrow particle size distribution. Treatment with hydrogen in the temperature range 773-923 K yields Pt/Si alloys at lower temperatures and platinum silicides (Pt3Si and Pt12Si5) at higher temperatures. The CO chemisorption shows that with increasing degree of alloying (1) the nu(CO)(l) and the nu(CO)(b) band shifts to lower wavenumbers, (2) the intensity of the nu(CO)(l) band decreases and (3) the nu(CO)(b)/nu(CO)(l) intensity ratio increases. The phenomena are interpreted by simultaneous effects of Pt surface dilution, enhanced electron back-donation from platinum to CO and Pt d-band narrowing.
引用
收藏
页码:195 / 199
页数:5
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