کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6468636 | 1362319 | 2017 | 9 صفحه PDF | دانلود رایگان |
NiMgAl-based catalysts were synthesized by coprecipitation, sol-gel, and impregnation methods, calcined at 700 °C for 4 h and tested in partial oxidation of methane in a temperature range of 500-800 °C. The fresh and used unsupported and supported samples were characterized by X-ray diffraction, nitrogen physisorption with Brunauer-Emett-Teller (BET) analysis, and H2-temperature-programmed reduction. X-ray diffraction analysis showed, for all samples, the formation of spinel phases MgAl2O4 and/or NiAl2O4 with crystallite sizes of 6-14 nm. H2-temperature-programmed reduction analysis showed reduction of two Ni2+ species (in octahedral and tetrahedral sites of a spinel structure) into metallic nickel known to be responsible for the methane activation. The 10 wt % Ni/MgAl2O4 impregnated catalysts exhibited the highest activity and stability in the partial oxidation of methane reaction, which led mainly to syngas (CO + H2) at 800 °C with a methane conversion close to the thermodynamic equilibrium (95%). A kinetic model revealed that the oxidation of methane occurs on a thin layer of the catalytic bed in which oxygen is consumed and is followed by the production of CO and H2 by methane steam reforming and water gas shift reactions.
Journal: Comptes Rendus Chimie - Volume 20, Issue 7, July 2017, Pages 738-746