METHANOL SYNTHESIS BY AMORPHOUS COPPER-BASED CATALYSTS PREPARED BY SPARK-EROSION

Amorphous metallic powders, with compositions: Cu70Zr30, Cu70Zn30 and Cu70Zn15Al15, were prepared by a spark-erosion technique, using kerosene as the dielectric. Two of them, viz. Cu70Zr30 and Cu70Zn15Al15, were obtained in a fully amorphous state, whereas some crystalline copper was detected in the Cu70Zn30 sample. Specific surface areas were measured for these spark-eroded powders and were several orders of magnitude higher than those of traditional amorphous ribbons prepared by melt-spinning. SEM analysis indicated that the powders were in fact very small, spherical, metallic particles ( < 1.5 mum diameter), highly dispersed in a carbon matrix of large surface area. These powders were found to be active for the synthesis of methanol from both CO + H, and CO2 + H-2. The steady-state rate of methanol production from CO2 + H-2 was greater than that measured from CO + H-2. This indicates that methanol is produced preferentially from carbon dioxide. Steady-state selectivities to methanol of over 99 mol-% were observed for CO2 + H-2, whereas only 75-90 mol-% of methanol was formed from CO + H-2 as reactants.