Développement et synthèse de deux séries de catalyseurs à base de bentonite et d'oxydes mixtes. Application à la déshydrogénation oxydante du méthane. - TEL - Thèses en ligne Accéder directement au contenu
Thèse Année : 2011

Development and synthesis of two serie of catalysts based on bentonite and mixed oxides. Application to the oxidative dehydrogenation of methane.

Développement et synthèse de deux séries de catalyseurs à base de bentonite et d'oxydes mixtes. Application à la déshydrogénation oxydante du méthane.

Résumé

A natural Maghnia clay was pillared by Al13 and impregnated by 3-10 wt.% Me (Me = Rh, Ni, Pd, Ce) to be used as catalysts in the reforming of methane with carbon dioxide to synthesis gas. The structural and textural properties of materials calcined at 450°C were determined by several techniques (XRD, FT-IR, 27Al magic angle spinning (MAS) NMR, X-ray photoelectron spectroscopy (XPS), BET, thermogravimetric analysis (TGA)- DSC, H2-temperature programmed reduction (TPR) and NH3-TPR). Although impurities are present in the Al-pillared layered clay (PILC) support, most properties are close to those of pure Al-pillared Na-montmorillonite. Impregnation and calcination leads to the plugging of most micropores by clusters or microparticles of oxides. The NMR resonances of AlVI and AlIV specie are not modified after impregnation, and AlVI/AlIV ratio only varies on loading when compared to Al-PILC. Catalytic experiments show that the most active catalyst is 3%Rh/Al-PILC on which 88 mol.% of methane is converted at 650°C with a minimum amount of carbon deposit. The conversions decrease along the 3% Rh-10% Ni > 3%Pd > 3% Ni > 3% Ce series. The H2/CO ratio amounts to 1.1 with Rh and to 0.85 with Pd which are metallic at the temperature of reaction, but it has a lower value with Ni and Ce due to the RWGS reaction known to proceed in the presence of oxides.
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Dates et versions

tel-00768814 , version 1 (24-12-2012)

Identifiants

  • HAL Id : tel-00768814 , version 1

Citer

Siham Barama. Développement et synthèse de deux séries de catalyseurs à base de bentonite et d'oxydes mixtes. Application à la déshydrogénation oxydante du méthane.. Catalyse. Université des Sciences et de la Technologie Houari Boumediene, 2011. Français. ⟨NNT : 10/2011-D/CH⟩. ⟨tel-00768814⟩
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