The effects of Fe, Mg, and Pt-doping on the improvement of Ni stabilized on Al2O3-CeO3 catalysts for methane dry reforming

Abstract

Herein, the promotional effects of Mg, Fe, and Pt on Ni-based catalysts supported on Al₂O₃-CeO₂ (Ni/Al₂O₃-CeO₂) were investigated in the dry reforming of methane (DRM) reaction. The interaction of a suitable amount of MgO and FeO with Ce₂O₃ stabilized in the catalysts was demonstrated by the temperature-programmed desorption of CO₂ (CO₂-TPD). Ce₂O₃ has a high basicity for adsorbing CO₂, generating a monoclinic Ce₂O₂CO₃ species in the DRM reaction. Surface oxygen ions were also produced by adding MgO and FeO, as demonstrated by the temperature-programmed reduction of H₂ (H₂-TPR). Monoclinic Ce₂O₂CO₃ and surface oxygen may both be used to oxidize and remove the carbon that was deposited, maintaining the high activity and stability of the metal Ni and Pt catalysts. The high dispersion and synergistic interactions between the platinum and oxide phases, which are associated with the decrease in reduction temperature and the rise in the number of basic sites, are responsible for the increased activity of Pt with M–Ni/Al₂O₃-CeO₂ catalysts. The co-doped Ni/Al₂O₃-CeO₂ catalysts with Mg and Fe significantly enhanced the activity (more than 80% methane and 84% CO₂ conversion), the selectivity toward syngas (∼90%), and maintained the H₂/CO ratio at about 0.97 at 700 °C.