Effect of Ba Addition on the Catalytic Performance of NiO/CeO2 Catalysts for Methane Combustion

Abstract

Methane catalytic combustion, a method for efficient methane utilization, features high energy efficiency and low emissions. The key to this process is the development of highly active and stable catalysts. This study involved the synthesis of a range of catalysts, including NiO/CeO2, NiO–M/CeO2, and NiO-Ba/CeO2. In order to modify the NiO/CeO2 catalysts to improve their catalytic activity, various alkaline earth metal ions were introduced, and the catalysts were characterized to evaluate the impact of different alkaline earth metal ion doping. It was found that the introduction of Ba as a dopant yielded the highest catalytic activity among the dopants tested. Based on this, the influence of the impregnation sequence, the Ba loading amount, and other factors on the catalytic activity of the NiO/CeO2 catalysts doped with Ba were investigated, and comprehensive characterization was conducted using a variety of analytical techniques, including N2 adsorption/desorption, X-ray diffraction, Fourier transform infrared, hydrogen temperature-programmed reduction, methane temperature-programmed surface reaction, and oxygen temperature-programmed oxidation. The H2–TPR characterization results suggest that Ba introduction partially enhances the reducing property of NiO/CeO2 catalysts, and improves the surface oxygen activity in the catalysts. Meanwhile, the CH4–TPSR and O2–TPO results indicate that Ba introduction also boosts the bulk-phase oxygen liquidity in the catalysts, renders the migration of bulk-phase oxygen to surface oxygen, and increases the surface oxygen number in the catalysts. These results provide evidence of the effectiveness of this catalyst in methane catalytic combustion.