Caractérisation de catalyseurs Rh/Al2O3 par adsorption de gaz et par spectroscopie de photoélectrons X
| Autor: | Duprez, Daniel, Delahay, Gerard, Abderrahim, Hocine, Grimblot, Jean |
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| Přispěvatelé: | Laboratoire de Catalyse en Chimie Organique (LCO), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Laboratoire de catalyse hétérogène et homogène, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | francouzština |
| Rok vydání: | 1986 |
| Předmět: | |
| Zdroj: | Journal de Chimie Physique Journal de Chimie Physique, 1986, 83, pp.465-471. ⟨10.1051/jcp/1986830465⟩ |
| DOI: | 10.1051/jcp/1986830465⟩ |
| Popis: | International audience; Three series of Rh/Al2O3 catalysts were characterized by chemisorption of gases, titrations., temperature-programmed reduction, and XPS. The temperature of calcination (393-1173 K), the temp. of redn. (773-1173 K), and the introduction of steam in the pretreatment (723 K) were varied. Air calcination at >823 K leads to catalysts partially reducible at 773 K, with sintering of the reduced phase. The diffuse oxide phase (D.O.P.) thus created is very stable. Pure steam substantially increases the formation of this little reducible oxide phase. Treatment under H2 at >773 K leads to sintering of Rh particles, which remain totally reducible at 773 K. The presence of H2 in steam suppresses the appearance of the D.O.P., which can be formed by diffusion of Rh3+ ions in the Al2O3 matrix. The presence of D.O.P. does not influence the reducibility of surface Rh2O3, which depends essentially on its dispersion: the smaller the oxide particles, the higher their temp. of redn. The binding energy of Rh, measured by XPS, depends on the metal particle size. No metal-oxide interaction was found in the partially reduced samples. Binding energies of Rh3+ in the D.O.P. are higher than in Rh2O3. |
| Databáze: | OpenAIRE |
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