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Rhodium Dispersion in a Rh/Ce 0.68 Zr 0.32 O 2 Catalyst Investigated by HRTEM and H 2 Chemisorption

2000; American Chemical Society; Volume: 104; Issue: 19 Linguagem: Inglês

10.1021/jp994101z

1520-6106

José M. Gatica, Richard T. Baker, Paolo Fornasiero, Serafı́n Bernal, Ginesa Blanco, Jan Kašpar,

Catalysis and Hydrodesulfurization Studies

The effect of reduction temperature on the hydrogen adsorption and Rh dispersion in a Rh/Ce0.68Zr0.32O2 catalyst with texturally stable Ce0.68Zr0.32O2 support was investigated. Rh dispersion data were also obtained from Rh particle size analyses made using high-resolution transmission electron microscopy (HRTEM) images. Comparison of the dispersion values obtained by using the two techniques showed that H2 adsorption at −80 °C is a suitable tool for the estimation of Rh dispersion at reduction temperature, Tred, ≤500 °C. For Tred > 500 °C, a partial suppression of H2 chemisorption was observed. However, after a mild reoxidation and low temperature reduction, the H2 adsorption capacity of these samples was regenerated and good agreement with the HRTEM data was again obtained.