CO₂ methanation catalysts prepared from amorphous Ni-Zr-Sm and Ni-Zr-misch metal alloy precursors

Nickel catalysts supported on nano-grained oxides have been prepared from amorphous Ni-Zr-Sm and Ni-Zr-Mm (Mm: misch metal) alloys and crystalline Ni-Sm and Ni-Mm alloys. These catalysts show higher catalytic activity for methanation of carbon dioxide than a conventionally prepared zirconia supported nickel catalyst. The catalytic activity of Ni-Zr-5 at% Sm catalysts increases with increase in nickel content, and is higher than the samarium-free Ni-Zr catalysts containing the same amount of nickel. The stabilization of tetragonal zirconia and the increase in the number of active surface nickel sites by addition of samarium to the nickel-rich catalysts leads to enhancement of catalytic activity. In the Ni-Zr-5 at% Mm catalysts, only the activity of the catalyst containing 60 at% nickel is enhanced in comparison with misch metal-free Ni-Zr catalysts. It is also found that Ni-Sm and Ni-Mm catalysts show activities as high as that of Ni-Zr catalyst, suggesting that samarium and misch metal oxides also act as good catalyst supports for methanation catalysts.