Combined infrared and mass spectrometric study of reactions of adsorbed NO and CO on 0.5 wt% Rb/SiO2 catalyst

被引:22
作者
Chuang, SSC
Tan, CD
机构
[1] Department of Chemical Engineering, University of Akron, Akron
关键词
infrared spectroscopy; mass spectroscopy; Rh/SiO2; catalyst;
D O I
10.1016/S0920-5861(96)00216-7
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
NO adsorption, CO adsorption, NO temperature-pro rammed desorption and decomposition (TPD), and temperature-programmed reaction (TPR) of NO-CO have been studied over 0.5 wt% Rh/SiO2 catalysts by a combined infrared and mass spectrometric technique. Infrared study reveals that the high wavenumber Rh-NOdelta- at 1723-1740 cm(-1) is the dominant adsorbate during TPD and TPR with NO:CO = 1:1. During TPR, CO reduces part of Rh surface resulting in the formation of the low wavenumber Rh-NOdelta- at 1634-1680 cm(-1). Increasing CO partial pressure (i) promotes the formation of Rh-0 sites, producing linear CO, (ii) increases the selectivity to N2O below the light-off temperature, (iii) raises the light-off temperature, and (iv) promotes the formation of Si-NCO and Rh-NCO. Comparison of results of the present study with those of previous studies on 4 wt% Rh/SiO2 shows that different dispersion of Rh crystallites on SiO2 support results in significant variation in chemisorptive and reactive properties of Rh metal for the NO-CO reaction.
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页码:369 / 377
页数:9
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