Transition metals, metal oxides and metal-containing mixed oxides have been extensively used for Fischer-Tropsch hydrocarbon synthesis (1–9) and their ability to yield oxygenated compounds. During the last two decades, an extensive search has been carried out in examining the mechanism of catalytic hydrogenation of co and CO, which produced hydrocarbons and oxygenate compounds. The catalytic models for hydrocarbon synthesis have already been reviewed by Vannice (lo), which gives detailed information and discusses the data which were obtained during their development. As a broad product distribution is obtained during the FT synthesis, the mechanisms are extremely complicated and not clearly understood: therefore this topic is beyond the objective of this chapter and hence no further attention will be paid.