CO oxidation catalyzed by Ag/SBA-15 catalysts: Influence of the hydrothermal treatment |
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Institution: | 1. Laboratoire des matériaux, surfaces et procédés pour la catalyse (LMSPC), UMR 7515 du CNRS, université de Strasbourg (UDS), 25, rue Becquerel, 67087 Strasbourg cedex, France;2. Laboratoire de génie des procédés chimiques (LGPC), université Ferhat-Abbas, 1900 Sétif, Algeria |
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Abstract: | Four types of SBA-15 were prepared with different times and temperatures of treatment in order to obtain a range of micropore sizes. CO oxidation was used as a probe reaction in order to evaluate the nature of the active species when SBA-15s were doped with ca 10% Ag deposited from an AgNO3 solution and calcined or reduced at 350 °C. The texture (TEM, nitrogen physisorption), structure (XRD) and reducibility (TPR) of the various catalysts (Ag/SBA-15) were studied and compared to those of a catalyst prepared by deposition of silver on fumed silica as a reference. These catalysts differ initially by the nature of silica and by pore sizes. In CO oxidation, pre-reduced catalysts are more active than pre-oxidised ones. This has to do with two phenomena, i.e. sintering, which produces large inactive silver particles, and formation of active silver species in the form of small Ag2O particles. |
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Keywords: | SBA-15 Silver catalysis CO oxidation Silver nano-particles Double-solvent technique |
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