Fabrication of spiral-structured Ni–Ce catalyst supported on natural kaolin-derived metakaolin for CO<inf>2</inf> methanation

Abstract

An efficient process for CO2 utilization by converting into CH4 via catalytic methanation of CO2 has recently received great attention, as it enables a complete mitigation of CO2 with a high potential for industrial scale applications. The better management of heat generated by this highly exothermic reaction together with the improved catalyst material containing high metal loading are a crucial step to advance the process for large scale production. In this study, nickel (Ni) and cerium (Ce) as a metal catalyst and a catalytic promoter supported onto a natural kaolin-derived metakaolin (MTK) was prepared by a one-step co-impregnation using microwave-assisted hydrothermal process. The microwave-assisted hydrothermal synthesis can produce the catalyst with highly dispersed Ni active phases and Ce promoter at high Ni loading of 30% and Ce loading of 20%. Subsequently, the spiral-structured Ni–Ce/MTK catalyst was fabricated by wash coating of a Ni–Ce/MTK slurry onto an aluminum (Al) substrate with spiral shape. The effects of spiral-type catalysts with different twist angles of 0°, 270°, and 360° for high feed rate CO2 methanation were investigated and compared with the counterpart of granular catalyst. As a result, the spiral-structured catalysts presented better catalytic performances ascribed to the enhanced heat and mass transfer by swirling flow, eliminating the formation of hotspots on the catalyst. The spiral twist of 270° was the most appropriate angle to obtain the best CO2 methanation activity. In addition, a durability test of the spiral-structured catalysts demonstrated that a slight decline in CO2 conversion from 67.9% to 58.7% was observed throughout a 1000-h test.