Hydrogen production over partial oxidation of methane using NiMgAl spinel catalysts: A kinetic approach

Abstract

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