Enhanced low-temperature activity for CO2 methanation over NiMgAl/SiC composite catalysts

BackgroundCarbon dioxide (CO2) methanation is an important reaction in energy and environmental fields, which aims to convert CO2 into natural gas with hydrogen (H-2) from renewable sources. One of the technical bottlenecks for CO2 methanation is the lack of feasible catalysts, especially the ones with satisfactory low-temperature activity. ResultsThe NiMgAl/SiC composite catalyst that was derived from hydrotalcite precursor on the SiC substrate possessed enhanced low-temperature activity and excellent long-term stability in CO2 methanation. For the low-temperature activity, CO2 conversion reached 63.8% and 74.5% at 300 and 325 degrees C respectively. For the long-term stability, CO2 conversion merely decreased from 78.4% to 76.9% after 50h of reaction at 400 degrees C. ConclusionThe NiMgAl/SiC composite catalyst was successfully synthesized by the co-precipitation method, which exhibited enhanced low-temperature methanation activity compared with the NiMgAl and Ni/SiC catalysts. The superior low-temperature activity was mainly ascribed to two structural parameters. One was the small nickel (Ni) nanoparticle size, which was endowed by the unique structure of the hydrotalcite precursor. The other one was the high reducibility of Ni species, which was rendered by the appropriate metal-support interactions. The present work provides guidelines for the synthesis of highly efficient composite catalysts for energy and environmental applications. (c) 2019 Society of Chemical Industry