Promotion of Mn doped Co/CNTs catalysts for CO hydrogenation to light olefins

With various contents, Mn was introduced into carbon nanotubes (CNTs) supported cobalt catalysts and the obtained Mn-Co/CNTs catalysts were investigated for CO hydrogenation to light alkenes and characterized by N2 adsorption, X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), H2 temperature programmed reduction (TPR), CO temperature programmed desorption (TPD) and transmission electron microscope (TEM). The results indicate that the addition of a small amount of Mn (0.3 wt%) to CNTs-supported Co catalyst significantly increased the selectivity of C2-C4 olefins and decreased the selectivity of CH4. However, with further addition of Mn to the cobalt catalysts, the CH4 selectivity decreased obviously along with the increase of the C5+ selectivity. Compared with the unpromoted catalysts, the Mn-promoted cobalt catalysts increased the C2-C4/C20-C40 molar ratio.