Deoxygenation of triolein to green diesel in the H₂-free condition: Effect of transition metal oxide supported on zeolite Y

H₂-free deoxygenation is a very important process in producing high-quality biofuel without the use of H₂ gas supply. Considering the costly price of the noble metals, transition metal (TM) based catalysts are more affordable, and the performance is comparable to the noble metal-based catalyst. In this study, TMO supported on zeolite Y catalysts (Ni-, Cu-, Co-, Zn- and Mn-Y) are prepared via wet-impregnation for deoxygenation of triolein, a model compound of non-edible oil under H₂-free condition. The deoxygenation activity of TMO supported on zeolite Y is following the order of Ni-Y > Co-Y > Cu-Y > Mn-Y > Zn-Y. The nickel oxide supported on zeolite-Y (Ni-Y) shows the highest conversion up to 76.21 % with 84.28 % hydrocarbon selectivity after reacted at 380 °C for 2 h. Besides, the selectivity toward diesel range hydrocarbon is 92.61 %. The superior deoxygenation activity of Ni-Y can be related to synergistic effect between the reduced B/L and high hydrogenolysis ability of Ni that promote the decarboxylation reaction, suppress the cracking and polymerization of heavy hydrocarbon. Therefore, Ni-Y is a potential catalyst to obtain high quality green diesel from non-edible oil through catalytic deoxygenation without addition of external H₂ source.