New hybrid catalysts for Fischer-Tropsch synthesis (FTS) to selectively produce isoparaffins at one step were developed by using Fe FTS catalysts mixed with H-ZSM-5 zeolite. The FTS catalysts produced normal paraffins, and then the normal paraffins isomerized and hydrocracked to produce isoparaffins on the zeolite in situ. For preparing highly active hybrid catalysts to lower methane formation, FTS catalysts based on Fe were developed. Carbon monoxide was the most effective reducing gas for the Fe FTS catalysts and the hybrid catalysts. Before adding the zeolite, the FTS products contained normal paraffins from C1-C16. After adding the zeolite, heavy hydrocarbons disappeared, and light hydrocarbons contained isoparaffins from C1 to C10 were produced alternatively. These results indicated that the hybrid catalyst composed of the mixture of Fe FTS catalysts and ZSM-5 zeolite had high performance for producing isoparaffins via one-step reaction. (c) 2005 Elsevier B.V. All rights reserved.