Ce-promoted Ni/Ca-Al(O) coprecipitated catalysts with efficient synthetic natural gas generation at low temperatures

Abstract

In this study, we investigated the effect of Ce on Ni/Ca-Al catalysts for CO2 methanation prepared by coprecipitation. Our results showed that Ce promotion resulted in an increase in catalytic conversion at several space velocities, which was attributed to the decrease in the Ni(0) particle size and the enhancement of surface carbonate species formation. We found that the catalysts showed exceptional activity at low temperatures (85% conversion at 300 °C, 60 L g−1·h−1, and 15,000 h−1) and high stability without the formation of CO or coke for up to 20 h. The catalysts remained active under more challenging conditions and maintained their performance at very high flow rates. Using In Situ difusse reflectance infrared spectroscopy, we proposed that the reaction proceeds through the reduction of carbonate species to formate and formyl species, which are precursors of methoxy species, and eventually to CH4. However, the results indicated that Ce did not change the methanation mechanism but rather increased the number of intermediate species formed. The findings highlighted the potential of Ce-promoted Ni/Ca-Al catalysts for the methanation of CO2 and provided valuable insights into their catalytic performance.