Constructing the Ni-O-Ce interface to enhance the activity and stability for partial oxidation of methane to syngas under high temperatures

Abstract

Catalyst interface determines the activity and stability of partial oxidation of methane (POM) toward syngas under high temperatures crucially. Herein, Ni catalysts supported on CeO₂ were prepared under different pretreatment atmospheres to construct an optimal and robust interface. Ni/CeO₂ catalyst pretreated in H₂ (Ni/CeO₂-H₂) exhibits the higher activity and the better stability than Ni/CeO₂-Ar and Ni/CeO₂-air catalysts. The Ni-O-Ce interfacial site in Ni/CeO₂-H₂ catalyst shows the lower reduction temperature, indicating the enhanced H-spillover effect and enhanced oxidation resistance of Ni under POM conditions. Moreover, the XPS and in situ Raman results show that Ni/CeO₂-H₂ contains more surface oxygen vacancies for adsorbing and activating oxygen, further contributing to the reaction activity. The in situ DRIFTS results indicate that the CH₄ could react with the lattice oxygen to form formate and carbonate, and further decompose to CO and CO₂. These findings deepen the fundamental understanding of Ni/CeO₂ catalysts for POM reaction.