Selective methanation of CO in H2-rich gas stream by synthetic nickel-containing smectite based catalysts

• Synthetic Ni-containing smectite is active for selective CO methanation.
• Doping of Pt can improve the activity of nickel-containing smectite catalyst.
• Number of exposed Ni species is improved by the presence of Pt dopant.
• Pt dopant can facilitate the reduction of Ni species in the lattice.

The selective methanation of CO in a H2-rich gas stream has been investigated with nickel catalysts including synthetic nickel-containing smectite (SM(Ni)) catalysts undoped and doped with platinum in small quantities and conventional nickel catalysts on SiO2, Al2O3, ZrO2, and MgO. The nickel content in SM(Ni) and the nickel loading in the other catalysts were the same, being 35 wt.%. The CO conversion with SM(Ni) was smaller than those with the conventional supported nickel catalysts at temperatures of 150–300 °C. However, the former showed the higher selectivity to the methanation of CO of >95% at 250 °C or below compared to the latter catalysts. The low activity of SM(Ni) was ascribed to a small area of exposed nickel species. The area of exposed nickel species was improved by doping a reduction promoter of platinum to SM(Ni), resulting in an increase in the activity while keeping the high selectivity to the CO methanation. The influence of reduction temperature and platinum loading on the activity and selectivity was investigated.

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