CO hydrogenation over Re-Co bimetallic catalysts supported over SiO2, Al2O3 and NaY zeolite

The promotion of rhenium on the reduction of Co2+ ions in cobalt based samples prepared by various methods, such as, sol/gel technique, incipient wetness impregnation of Al2O3 and NaY, has been investigated in the CO hydrogenation. Among the samples the reducibility of the sol/gel, Re-Co/Al2O3 and Re-Co/NaY (IM) were the highest compared to Re-Co/NaY (IE) [8]. In addition to facilitating reduction of Co2+ ions, the rhenium increased the rate of reaction and the formation of C5+ hydrocarbons at 10 bar pressures. The samples pretreated in various manner, revealed an about five fold increase in activity and an increase in the chain length in the NaY supported sample while the activity and selectivity changed in various way in the sol/gel prepared samples. Simultaneously, rhenium increased the amount of olefins of low carbon numbers. In the mechanism the rhenium provides an action preventing fast deactivation of cobalt.