Investigation of Carbon Dioxide Methanation over Ceria Based Catalysts

Abstract

The recycling technology by the catalytic conversion is one of the most promising techniques for the CO₂ treatment of gas burning power plant flue gases. The methanation of CO₂ to valuable product of CH₄shows significant environmental and economic benefits since the methane gas production can be used as a fuel to run the turbine for electricity generation. In addition, a highly basic catalyst such as ceria which has excellent redox properties is an effective material which could enhance carbon dioxide adsorption on the catalyst surface but has not been widely explored. Therefore, this research is focused on the development of ceria based catalysts by impregnating Ce to Ru/Mn/Al₂O₃ catalyst. From the catalytic testing, the addition of Ce to Ru/Mn/Al₂O₃ as based catalyst was found to be appreciably more active for promoting the CO₂methanation reaction. Further investigation of the Ru/Mn/Ce/Al₂O₃ catalysts on the ceria loading and calcination temperature can significantly affect the catalytic performance. The optimum conditions were achieved with 65 wt% of cerium loading and calcination temperature of 1000^oC which gave 97.73% CO₂ conversion with 91.31% of methane formation at reaction temperature of 200^oC. Meanwhile, only 30.52% methane was formed from 30.72% CO₂ conversion over Ru/Mn-65/Al₂O₃ catalyst. The high activity of Ru/Mn/Ce-65/Al₂O₃ catalyst can be ascribed to its high surface area caused by the production of new active sites on the catalyst surface since the morphology of the catalyst had transformed to look like staghorn coral morphology. Furthermore, incorporating the Ce towards Ru/Mn-65/Al₂O₃ catalyst had induced the formation of Al₂O₃ with different crystalline phase (from rhombohedral to orthorhombic phase) and formation of MnO₂ and Mn₂O₃.