CO_2 Methanation Catalysts Prepared from Amorphous Ni-Valve Metal Alloys Containing Platinum Group Elements

概要

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The amorphous Ni-valve metal (Ti, Zr, Nb and Ta) alloys containing a few at% of platinum group elements were activated by immersion into hydrofluoric acid and used for hydrogenation of carbon dioxide at 100-300℃. This surface activation led to formation of nanocrystalline surface alloys with high surface area, and to surface enrichment of platinum group elements on the titanium-, niobium- and tantalum-containing alloys, but not on the zirconium-containing alloys. The surface of the latter alloys was mainly composed of nickel. The activity and selectivity for methane formation on the titanium-, niobium- and tantalum-containing alloys were significantly affected by the difference in the platinum group elements; the ruthenium- and rhodium-containing alloys showed higher activity and selectivity for methane formation while the platinum-containing alloys exhibited the lowest activity for methane formation and produced mainly carbon monoxide. The zirconium-containing alloys showed the one order of magnitude higher activity for methanation of carbon dioxide in comparison with the titanium-, niobium- and tantalum-containing alloys and produced exclusively methane independent of platinum group elements contained. The alloying with zirconium seems very important to prepare the alloy catalysts having the extremely high activity.
東北大学の論文
1993-03-29