METHANATION BY CATALYSTS FORMED FROM INTERMETALLIC COMPOUNDS

The reaction of carbon monoxide with hydrogen (H2/CO = 3) to form methane was conducted over the temperature range 150-600°C over a number of untreated alloys and alloys which were oxidized at 350°C for 12 h (NixSiy, NixAly, CoxSiy, CoxAly, FexSiy, and FexAly). In both untreated and oxidized alloys Ni2Si, Ni5Si2, and Co2Si exhibited high activity for methane formation. Regarding the untreated alloys, the catalytic activity of the catalysts progressively increased during the reaction. X-ray diffraction patterns of the catalysts used showed transformation into silica and Ni or Co. It was concluded that the transformation of the alloys during the reaction resulted in an increase in active sites participating in the reaction. The catalytic activity of the oxidized alloys was essentially unchanged during the reaction. The oxidation treatment led to the transformation of alloys into a transition metal-supported catalyst, which exhibited higher activity than conventional oxide-supported methanation catalysts. Turnover numbers of the new supported catalysts, especially oxidized Ni5Si2, were several times larger than those of Ni supported on silica formed by conventional catalyst techniques. © 1979 American Chemical Society.