Alumina supported rhodium

Oh, S.H. (1990) Effects of cerium addition on the CO-NO reaction kinetics over alumina-supported rhodium catalysts, J. Catal. 124, 477. 

Routinely used X-ray sources are Mg Ka (1253.6 eV) and A1 Ka (1486.3 eV). In XPS one measures the intensity of photoelectrons N(E) as a function of their kinetic energy. The XPS spectrum, however, is usually a plot of N(E) versus Ek, or, more often, versus the binding energy Eb. Figure 3.3 shows the XPS spectrum of an alumina-supported rhodium catalyst, prepared by impregnating the support with... 

Preparation of Alumina-Supported Rhodium Model Catalysts... 

Figure 7 is a differential tunneling spectrum of CO chemisorbed on alumina supported rhodium particles. The identification of the peaks is also shown below and consist of three separate species. These are a gem dicarbonyl Rh (C0)2 a linear carbonyl RhCO and a bridging carbonyl RhxC0. The dicarbonyl is characterized by a peak at 4l3 cm 1 and the linear species by a bending mode at 465 cm-1. 

Figure 7 Differential tunneling spectrum of CO chemisorbed on alumina supported rhodium particles. Peak positions are not corrected for possible shifts due to the top lead electrode. Peak positions vary with rhodium coverage and CO exposure.

The stepwise mechanism was also shown later to be valid over supported platinum (55), and palladium 56, 56a) catalysts, as well as over alumina-supported rhodium (57). 

Due to the high density of Rh atoms, no species of the form Rh(C0)2 were formed, however. This is expected to be the case on the (111) surface as well. Weak absorptions between 400 and 575 cm"l were seen and are indicative of metal-absorbate stretching and bending vibrations. Inelastic electron tunneling spectroscopic (IETS) measurements on alumina supported rhodium particles (47, 48, 49) add little new structural information... 

Fuentes, S., and Figueras, F., The influence of particle size on the catalytic properties of alumina-supported rhodium catalysts. /. Catal. 61, 443 (1980). 

The oxidation of alumina-supported rhodium by oxygen in a temperature range between 280 and 870 K has been studied using calorimetry. The heat of dioxygen adsorption was found to vary only sHghtly with the dispersion of rhodium, with a value of 294 6 kJ moT 294 6 kJ mol [78]. 

Rupprechter G, Hayek K, Hofmeister H (1998) Electron microscopy of thin film model catalysts Activation of alumina supported rhodium nanoparticles. J Catal 173 409... 

Ferreira-Aparicio P, Femandez-Garcia M, Guerrero-Ruiz A, Rodriguez-Ramos I (2000) Evaluation of the role of the metal-support interfacial centers in the dry reforming of methane on alumina-supported rhodium catalysts. J Catal 190 2%-308... 

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