Methanation of syngas over coral reef-like Ni/Al2O3 catalysts

Coral reef-like Ni/Al2O3 catalysts were prepared by co-precipitation of nickel acetate and aluminium nitrate with sodium carbonate aqueous solution in the medium of ethylene glycolye. Methanation of syngas was carried out over coral reef-like Ni/Al2O3 catalysts in a continuous flow type fixed-bed reactor. The structure and properties of the fresh and used catalysts were studied by SEM, N-2 adsorption-desorption, XRD, H-2-TPR, O-2-TPO, TG and ICP-AES techniques. The results showed that the coral reef-like Ni/Al2O3 catalysts exhibited better activity than the conventional Ni/Al2O3-H2O catalysts. The activities of coral reef-like catalysts were in the order of Ni/Al2O3-673>Ni/Al2O3-573>Ni/Al(2)O(3-)473>Ni/Al2O3-773. Ni/Al2O3-673-EG catalyst showed not only good activity and improved stability but also superior resistance to carbon deposition, sintering, and Ni loss. Under the reaction conditions of CO/H-2 (molar ratio) = 1 : 3, 593 K, atmospheric pressure and a GHSV of 2500 h(-1), CH4 selectivity was 84.7%, and the CO conversion reached 98.2%.