HYDROGENATION OF CO2 INTO METHANOL AND DIMETHYL ETHER OVER HYBRID CATALYSTS

The development of technology for utilization of CO2 is of importance in recent years due to the greenhouse effect. The catalytic hydrogenation of CO2 into methanol and dimethyl ether was carried out over a hybrid-catalytic system. Different ratios of Cu/ZnO/Al2O3: zeolite catalysts have been formulated and characterized. The methanol-synthesis catalyst, Cu/ZnO/Al2O3 (CuO:ZnO:Al2O3 50:45:5), was prepared by a co-precipitation method. The copper catalyst was physically mixed with ZSM-5 zeolite at ratios of 1:1, 1:2 and 2:1. The hybrid catalysts were characterized using the x-ray diffraction method (XRD), temperature-programmed reduction (TPR), temperature-programmed desorption (TPD) of ammonia, nitrogen adsorption, scanning electron microscopy (SEM) and reactive frontal chromatography (RFC). The hydrogenation reaction was carried out in a tubular micro reactor at 250 °C and 40 bar using H2/CO2 feed ratios of 3 and 7. Products detected include methanol, dimethyl ether, carbon monoxide and water. Selectivity of products was depending upon the amount of copper-zeolite constituent and H2/CO2 feed ratio. The Cu/ZnO/Al2O3: zeolite hybrid catalysts showed over 30% CO2 conversion