An active and stable NiOMgO solid solution based catalysts prepared by paper assisted combustion synthesis for the dry reforming of methane

摘要

Ni supported on solid solution (NiOMgO) catalysts with different Ni concentration (10, 20 and 30 wt.%) were prepared by a novel paper assisted combustion synthesis (PACS) method, followed by a reduction stage. All as-synthesized materials formed NiOMgO solid solutions, which under optimum PACS conditions exhibited up to about 140 m(2)/g BET surface area, which is one of the highest reported so far for this type of materials. Solid solutions were not active unless reduced at higher temperatures, causing a fraction of the Ni to segregate to the surface to become the active sites. The activity during the dry reforming of methane was studied as a function of temperature, and time on stream (TOS). The PACS solid solution with 10 wt.% of Ni had the highest surface area and, upon reduction, it was the most active and stable catalyst exhibiting low carbon formation at 600 degrees C, and no carbon deposition at 700 degrees C during 24 h TOS. The activity results correlated well with the higher surface area of the starting solid solutions, the smaller Ni crystallite sizes, and the number of Ni2+ and Ni3+ sites on the surface.