Nanocomposites and nanomaterials

Ni-Fe, Co-Fe and Co-Ni nanocomposites based on carbon nanotubes in the reaction of CO2 methanation
Dyachenko A.G., Ischenko O.V., Prygunova O.V., Tsapyuk G.G., 
Matzui L.Yu, Gaidai S.V., Zakharova T.M., Yatsymyrskyi A.V
Taras Shevchenko National University of Kyiv, 64/13 Volodymyrs’ka str., Kyiv, Ukraine
E-mail: dyachenko.alla@yahoo.com

Global warming-induced climate change is one of the significant civilization threats of the modern times. Excess greenhouse gases, 82% of which are CO2, cause global warming. Therefore, in today’s world of high-energy demands, CO2 conversion and utilization seems to be a more attractive and promising solution. The CO2 hydrogenation to methane presents several advantages over other chemicals because it can be directly injected into already existing natural gas pipelines, and it can be used as a fuel or raw material for the production of chemicals. The methanation of carbon dioxide is an important catalytic process of fundamental academic interest with potential commercial application. Among the wide range of materials, bimetallic catalysts supported on carbon nanotubes occupy a special place.
CNT was used as support for preparation of Ni-Co, Ni-Fe, Co-Fe catalysts. The preparation of supported catalysts was provided by impregnation of carrier with nitrate solution of corresponding metals. Following the impregnation, the catalysts were air dried at 180 0C for 12 hours and then reduced under H2/He flow at 340 0C for 2 hours. The amount of applied active mass was 20 wt.% by weight of the carrier. The temperature dependence of catalytic performance over catalysts was examined with a supply of 2%CO2–55%H2–43%He and chromatography controlled. The crystal structure and surface morphology of the samples  after catalytic test were determined by XRD and SEM methods.
Resulting of catalytic test we can conclude 100% conversion of CO2 with CH4 yield: 73% – Co80Ni20/CNT, 64% – Co93Fe07/CNT, 85% – Ni80Fe20/CNT at 300 0C and atmospheric pressure. SEM EDX analysis of catalysts surface shows uneven distribution of actives over CNT. The metal grains with the size in the range of 10-50 nm are located on the external surface of CNT. It can be resumed that carbon nanotubes are a promising carrier of bimetallic catalysts for CO2 methanation process.