Formation and characteristic properties of carbonaceous species on nickel-magnesia solid solution catalysts during CH4-CO2 reforming reaction

Carbonaceous species formed during the reforming of CH4 with CO2 over a series of NixMg1-xO solid solution catalysts and MgO-supported Ni catalysts were characterized by temperature-programmed hydrogenation (TPH) method. Tao peaks appeared in the TPH spectra: one between 550 and 700 K (alpha-carbon) and another above 873 K (beta-carbon). It was found that a good relationship exists between the quantity of alpha-carbon species and the catalytic activity, indicating that alpha-carbon should be the reaction intermediate. In addition, the amount of beta-carbon increased with increasing reaction time, especially on the supported Ni/MgO catalysts which make inactive carbon during the CH4-CO2 reforming reaction. (C) 1997 Elsevier Science B.V.