Promoting Effect of Cobalt Addition on Higher Alcohols Synthesis over Copper-Based Catalysts

Abstract

The textural properties and microstructures of Co-modified Cu-based catalysts were investigated by N2 physisorption, X-ray diffraction (XRD), temperature-programmed reduction/desorption of hydrogen (H2-TPR/TPD) and scanning electron microscopy (SEM). Higher alcohols synthesis (HAS) was performed in a fixed bed reactor. The characterization results indicated that incorporation of cobalt in the Cu/γ-Al2O3 catalyst promoted the formation of CuCo2O4 crystallites, causing the decrease in BET surface area and pore volume. The gradual increase of CuCo2O4 concentration enhanced the adsorption of hydrogen on the surface layers, facilitating the formation of the well dispersed bimetal Cu-Co sites. In the HAS reaction, the catalytic activity of CO hydrogenation and space time yield of total alcohols presented an increasing trend with the increase in Co concentration. As the ratio of Co/Cu increased to 1, the catalyst produced the space time yield of 0.38 g.ml-1.h-1 and the selectivity of 65% for total alcohols, respectively. Moreover, higher Co concentration facilitated the product distribution shifting towards C2+OH.