Comparison of Non-noble Metal Catalysts in Lipid Hydrotreatment into Second-Generation Bio-diesel

To explore a green, cheap, and high-performance catalyst for lipid hydrotreatment into green diesel, the non-noble metal catalysts (Fe, Cu, Co, Ni, and Mo) with Al2O3 carrier were prepared. Their catalytic performance in oleic acid hydrotreatment was compared, and the metal loading was studied. The characterizations (XRD, N-2 physical sorption, H-2-TPR, and XPS) were utilized to elucidate the catalytic property. In oleic acid hydrotreatment, the catalytic activity of 5 monometallic catalysts was in the following order: Co > Mo > Ni > Fe > Cu, and the Co/Al2O3 catalyst achieved 94.4% conversion and 91.8% alkane yield. Among 6 Co loadings (5, 10, 15, 20, 25, and 30 wt%), 25 wt% was optimal because it reached the balance of the surface area and the number of Co active sites. Moreover, the lipid hydrotreatment over Co/Al2O3 catalyst occurred mainly via DCX/DCN route; meanwhile, the cracking reaction also happened.