초록 |
Natural gas is popular energy source globally, especially for transportation. However, emission of unburnt methane is observed from natural gas vehicles, which should be regulated for environmental protection. Catalytic combustion of methane is an effective method for reducing the methane emission. Among non-noble metal oxide catalysts, cobalt oxide is accepted as an active catalyst for oxidation reactions. In this work, mesoporous cobalt oxide catalyst was treated by nitric acid to modify its surface chemistry. Significant enhancement of methane oxidation activity was observed for the acid treated catalyst. By using various characterization techniques, it was revealed that defect sites, such as oxygen vacancy sites were formed during the acid treatment. Therefore, the acid treated catalyst possessed large amount of surface chemisorbed oxygen species, which was beneficial for the methane combustion reaction. |