Wednesday, June 5, 2019: 3:15 PM
Texas Ballroom EF (Grand Hyatt San Antonio)
Thien An Le1, Ji Eun Kim1, Jong Kyu Kang1 and Eun Duck Park1,2, (1)Department of Energy Systems Research, Ajou University, Suwon, Korea, Republic of (South), (2)Department of Chemical Engineering, Ajou University, Suwon, Korea, Republic of (South)
Much attention has been paid to develop non-fossil fuel energy sources to reduce the CO
2 emission and create a sustainable energy system for the future. Although methane is a well-known fossil fuel, it can also be synthesizd from CO and CO
2 through hydrogenation which is called Sabatier reaction. Methane is a versatile energy source that can be used directly for heat and electricity generation. It can be fueled to the compressed natural gas vehicles and be a viable option for renewable energy storage. Ni-based catalysts have been widely used in the commercial process to carry out the Sabatier reaction because of their relative fair activity, low cost, and high availability compared with the others. However, the easy deactivation at high temperatures caused by the metal sintering and coke deposition is still the big challenge for Ni catalyst. Furthermore, a highly exothermic nature of Sabatier reaction limits the complete conversion of reactants at high temperatures and causes the hot spots throughout the catalyst bed. Therefore, the development of catalysts active at low temperatures with high thermal conductivity is highly required for this reaction.
Until now, many kinds of supports combined with the novel preparation methods have been investigated to fabricate the Ni-based catalysts owning the high methanation catalytic activity at low temperatures with the high resistance of sintering and coking. Spinel aluminates (MAl2O4) have gained much interest as supports in catalysis because of their inherent properties including high thermal stability. The unique core-shell spinels MAl2O4@Al (M=Mn, Mg, Zn), which are obtained by a simple hydrothermal surface oxidation (HTSO) of Al metal particles in an aqueous solution of heterometal ions at elevated temperature (120-200 oC), are used as the supports for Ni catalysts for CO methanation. Various techniques including N2 physisorption, H2 chemisorption, H2-TPR, chemisorption, XRD, ICP-OES, in-situ FTIRS, STEM-EDX, and TEM are employed to characterize the catalysts.
The combination of the core-shell microstructures and spinel-type makes the outstanding catalytic performance of the Ni supported by MAl2O4@Al (except for ZnAl2O4@Al) for CO methanation compared to commercial γ-Al2O3 at low reaction temperatures due to the improvement of the dispersion of NiO nanoparticles, as well as the increase of the quantity of the reduced active Ni species. MnAl2O4@Al is considered as the best support for Ni-based catalysts for CO methanation. The good stability of Ni/MAl2O4@Al catalysts are also confirmed.
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