Sandwich-structured nickel/kaolinite catalyst with boosted stability for dry reforming of methane with carbon dioxide

Dry reforming of methane (DRM), catalytic conversion of carbon dioxide and methane into syngas, is an appealing process that converts two greenhouse gases into a versatile chemical feedstock. Design of efficient catalysts with high activity and stability is the key to perform the reaction. Unfortunately, the high reaction temperature of DRM often causes sintering and aggregation of the active metal particles in the catalysts (particularly Ni-based catalysts) and the consequent formation of deposited carbon results in rapid deactivation of the catalysts. One way to address this issue is to design confined catalysts. In this study, an “intercalation-etching” strategy to delaminate raw kaolinite into pitting-rich nanosheets was developed and a sandwich-structured Ni/kaolinite catalyst was fabricated by assembling Ni nanoparticles with the nanosheets. In contrast with Ni catalysts supported on raw kaolinite or acid-activated kaolinite, the sandwich-structured Ni/kaolinite catalyst remained highly steady with time on stream because of its confinement and isolation effect. Furthermore, the carbon deposits generated in the sandwich-structured catalyst were filamentous carbon, which was beneficial to the catalytic activity and stability. On the contrary, the carbon deposits generated in the reference catalysts were coated carbon, which caused the deactivation of the catalysts.