Promotion effect of additive Fe on Al2O3 supported Ni catalyst for CO2 methanation

In this paper, the effect of additive Fe on Ni/Al2O3 catalyst for CO2 methanation was studied. A series of bimetallic Ni-Fe catalysts with different Ni/Fe ratios were prepared by impregnation method. For comparison, monometallic Fe-based and Ni-based catalysts were also prepared by the same method. The characterization results showed that adding Fe to Ni catalyst on the premise of a low Ni loading(<= 12 wt.%) enhanced CO2 methanation performance. However, when the Ni loading reached 12 wt.%, the catalytic activity decreased with the increase of Fe content, but still higher than the corresponding Ni-based catalyst without Fe. Among them, the 12Ni3Fe catalyst exhibited the highest CO2 conversion of 84.3 % and nearly 100% CH4 selectivity at 50000 ml g(-1) h(-1) and 420 degrees C. The enhancement effect of adding Fe on CO2 methanation was attributed to the dual effect of suitable electronic environment and increased reducibility generated by Fe species.