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.