In situ DRIFTS characterization of wet-impregnated and sol-gel Pd/TiO2 for NO reduction with CH4

被引:14
作者
Karakas, G [1 ]
Mitome-Watson, J [1 ]
Ozkan, US [1 ]
机构
[1] Ohio State Univ, Dept Chem Engn, Columbus, OH 43210 USA
基金
美国国家科学基金会;
关键词
D O I
10.1016/S1566-7367(02)00094-8
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
The adsorption/desorption behavior of 2%Pd/TiO2 catalysts synthesized by wet-impregnation and modified sol-gel techniques were examined in NO-CH4-O-2, reaction using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The catalyst prepared by the modified sol-gel method showed significantly higher resistance toward oxygen while maintaining a 100% NO conversion. Under NO + CH4 + O-2 flow, the main adsorbed NO species was identified as the linearly adsorbed NO on metallic palladium (Pd-0-NO) at high temperatures. On the oxidized sample, the major NO species was found to be a bridged nitrate species. Pd-0-NO species was suggested to react with CHx to form surface NHx species. Over the sol-gel catalyst, the peak intensity for Pd-0-NO species was much higher than that over the impregnated catalyst. The DRIFTS data seem to suggest that this species could play a role in reduction of NO with CH4 over Pd/TiO2 catalysts. (C) 2002 Published by Elsevier Science B.V.
引用
收藏
页码:199 / 206
页数:8
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