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The catalytic performance during combined steam and carbon dioxide reforming of methane (SCR) was investigated on Ni/MgAl 2 O 4 catalyst promoted with CeO 2 . The SCR catalyst was prepared by co-impregnation method using nickel and cerium metal precursors on hydrotalcitelike MgAl 2 O 4 support. In terms of catalytic activity and stability, CeO 2 -promoted Ni/MgAl 2 O 4 catalyst is superior to Ni-CeO 2 /Al 2 O 3 or Ni/MgAl 2 O 4 catalysts because of high resistance to coke formation and suppressed aggregation of nickel particles. The role of CeO 2 on Ni/MgAl 2 O 4 catalyst was elucidated by carrying out the various characterization methods in the viewpoint of the aggregation of nickel particles and metal-support interactions. The observed superior catalytic performance on CeO 2 -promoted Ni/MgAl 2 O 4 catalyst at the weight ratio of MgO/Al 2 O 3 of 3/7 seems to be closely related to high dispersion and low aggregation of active metals due to their strong interaction with the MgAl 2 O 4 support and the adjacent contact of Ni and CeO 2 species. The CeO 2 promoter also plays an important role to suppress particle aggregation by forming an appropriate interaction of NiO-CeO 2 as well as Ni-MgAl 2 O 4 with the concomitant enhancement of mobile oxygen content.

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The effect of precursors, such as copper nitrate, acetate, and chloride, on the bifunctional CuÀZnO/γ-Al 2 O 3 catalysts was investigated for the direct dimethyl ether (DME) synthesis from syngas. The catalysts were characterized by measuring the reducibility and the surface area of metallic copper, together with their acidity. The well-dispersed copper particles with a high reducibility as well as a large amount of weak acidic sites on the bifunctional CuÀZnO/γ-Al 2 O 3 catalysts, prepared from a copper acetate precursor, are responsible for its high catalytic activity. The quantity of the acidic sites is a more crucial factor for obtaining a high DME yield than the surface area of metallic copper on the bifunctional catalyst.