Ni/Al2O3 catalysts for syngas methanation: Effect of Mn promoter

Ni/Al₂O₃ catalysts with different amounts of manganese ranging from 1 to 3 wt% as promoter were prepared by co-impregnation method. The catalysts were characterized by N₂ physisorption, XRD, TPR, SEM and TEM. Their catalytic activity towards syngas methanation reaction was also investigated using a fixed-bed integral reactor. It was demonstrated that the addition of manganese to Ni/Al₂O₃ catalysts can increase the catalyst surface area and average pore volume, but decrease NiO crystallite size, leading to higher activity and stability. The effects of reaction temperature, pressure and weight hourly space velocity (WHSV) on carbon oxides conversion and CH₄ formation rate were also studied. High carbon oxides conversion, CH₄ selectivity and formation rate were achieved at the reaction temperature range of 280–300 °C.