The hydrogenation of carbon dioxide using a Cu-Zn-Cr oxide/zeolite composite catalyst system has been studied. The change in the structure of the oxide catalyst during the reaction was found to be very significant, with the catalytic activity decreasing rapidly at temperatures over 350-degrees-C. Measurement of metallic copper surface areas revealed a sharp decrease in exposed metallic copper caused by the sintering of the catalyst. The reaction of methanol over various composite catalyst was also examined. The results indicated that composite catalysts with low metallic copper surface areas promote the methanol to gasoline reaction, while high surface areas caused the decomposition of methanol to carbon monoxide and carbon dioxide. These results suggested that hydrocarbon synthesis and the decomposition of methanol are competitive.