Synthesis, characterization and properties of anti-sintering nickel incorporated MCM-41 methanation catalysts

Several nickel incorporated MCM-41 catalysts with a nickel molar content from 1% to 10% were prepared by a hydrothermal synthesis method, and investigated for their catalytic performances for the production of substitute natural gas (SNG) from syngas methanation in a continuous flow fixed-bed reactor. The catalysts were characterized by FTIR, ICP, XRD, H2-TPR, TG-DTA and TEM, and the results showed that the mesoporous structure of MCM-41 still maintained well when the incorporated Ni molar content was up to 10%. The Ni-M catalyst prepared by the hydrothermal synthesis method with a nickel molar content of 10% showed the best catalytic activity with a high CO conversion of almost 100%, and a CH4 yield of 95.7% at 350 °C with 3:1 molar ratio of H2 to CO under 1.0 MPa and 12000 ml/h/g. Compared with the 10%Ni/M catalyst prepared by the impregnation method, the 10%Ni-M catalyst showed a higher resistance to sintering and no decrease in catalytic activity after calcination at 700 °C for 2 h. In the 100 h stability test under atmospheric pressure, the CO conversion rate and the CH4 yield obtained on 10%Ni-M catalyst maintained at about 100% and 82%, respectively, suggesting an excellent catalytic stability of this catalyst. The results of XRD, H2-TPR and TG-DTA showed that there was a strong interaction between the Ni species and the support, which inhibited the catalyst sintering. And the amount of coke formed on the spent 10%Ni-M catalyst in the stability test was 3.0 wt%. The coke formation was relatively easily to remove by calcination because the deposited carbon had a small particle size and uniform dispersion on the catalyst.