Comparative study at low and medium reaction temperatures of syngas production by methane reforming with carbon dioxide over silica and alumina supported catalysts

Two series of transition metals (Co, Ni, Ru, Ph, Ir, Pt) based catalysts have been prepared using silica and gamma-alumina. Their activity and stability for the dry reforming of methane in the temperature interval from 673 up to 1023 K have been examined and compared. The obtained results show that the support exerts a great influence on the turnover frequency of a given metal but deactivation occurring under reaction conditions mainly depends on the nature of the active metallic phase. Some of the catalysts suffer deactivation processes at temperatures close to 1023 K, that can be ascribed to sintering, and in only some cases, also to carbon deposition. At low reaction temperatures, i.e. 723 K, deactivation was only observed over supported iridium. Among all tested catalysts, those based on nickel, cobalt and rhodium appear to be the most resistant to deactivation processes under our experimental conditions and for the whole temperature range up to 1023 K. Among them, supported rhodium catalysts show an excellent stability, though alumina supported rhodium exhibits a much higher turnover frequency. (C) 1998 Elsevier Science B.V.