Promotional effects in alumina and silica supported bimetallic Ni–Fe catalysts during CO2 hydrogenation

• Fe promotes alumina and silica supported nickel catalyst during CO2 hydrogenation.
• Support affects the activity and amount of enhancement in conversion and yield.
• Total metal loading does not appear to affect the enhancement.
• Enhancement due to alloy formation, increase in metal sites and/or CO2 adsorption.

Nickel (Ni), iron (Fe) and three series of Ni–Fe bimetallic catalysts supported on alumina and silica were tested for the CO2 hydrogenation reaction at 448–548 K. The supported Ni–Fe catalysts containing 75 wt.% of the total metal loading as Ni and 25 wt.% as Fe showed a significantly better CO2 conversion and higher methane (CH4) yield compared to the Ni and Fe supported catalysts. Furthermore, the enhancements of conversion and yield were higher for the alumina supported catalysts than for the silica supported catalysts. The enhancements appear to be independent of total metal loading. It appears that the enhancements of conversion and yield were due to the formation of a suitable Ni–Fe alloy, and/or increase in the number of metal sites, and/or the availability of adsorbed CO2 species.

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