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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.

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Fischer-Tropsch Synthesis (FTS) on Fe-Cu-K/ ZSM5 catalysts prepared by varying the amount of active components for a given amount of ZSM5 has been investigated to elucidate the effects of iron concentration. The catalysts were prepared by conventional wet impregnation method using ZSM5 and subsequently calcined at 500°C for 5 h. The different catalytic performance is verified by the variation of microporosity such as surface area and pore size distribution of Fe-Cu-K/ZSM5, acidity, reducibility of active phases and the presence of various crystalline phases like a-Fe 2 O 3 , metallic iron and iron carbide. The characterization results are analyzed along with catalytic performance to arrive at optimum amount of active components and to obtain maximum selectivity of FTS products with high conversion of CO during FTS reaction.

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In this study, nickel-based reforming catalysts were synthesized for the reforming of toluene, a major component of thinners and widely used as an organic solvent. The reaction characteristics of these catalysts were investigated by both steam reforming and auto-thermal reforming. Reforming aromatic hydrocarbons like toluene to produce synthesis gas is difficult because carbon deposition also occurs, and the deposition of carbon lowers the activity of the catalyst and causes a pressure drop during the reaction process. In order to maintain a stable reforming process, a catalytic reaction technique capable of suppressing carbon deposition is required. Steam reforming and auto-thermal reforming of toluene were used in this study, and the temperature of the catalyst bed was remarkably reduced, due to a strong endothermic reaction during the reforming process. By using scanning electric microscopy (SEM), X-ray diffraction (XRD), and temperature-programmed oxidation analysis, it is shown that carbon deposition was markedly generated due to a catalyst bed temperature decrease. In this study, optimum conditions for catalyst composition and the reforming reaction are proposed to suppress the formation of carbon on the catalyst surface, and to remove the generated carbon from the process. In addition, ceria and zirconia were added as catalytic promoters to inhibit carbon deposition on the catalyst surface, and the carbon deposition phenomena according to the catalyst's promoter content were investigated. The results showed that the carbon deposition inhibition function of CeO 2 , via its redox properties, is insignificant in steam reforming, but is notably effective in the auto-thermal reforming of toluene.

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