Fe-promoted Ni catalyst with extremely high loading and oxygen vacancy for lipid deoxygenation into green diesel

Abstract

The catalytic performance of Ni catalyst in lipid deoxygenation into green diesel is commonly limited by the quantity of accessible active sites, the specific surface area, and the acidity of the catalyst. To cope with these problems, the Fe-promoted Ni catalyst on ZrO2 with 60 wt% Ni loading (60%Ni–Fe/ZrO2) is synthesized by the co-precipitation method. The deoxygenation of oleic acid over 60%Ni–Fe/ZrO2 catalyst attained 98.7% conversion and 91.8% alkane yield, much higher than that of 20%Ni–Fe/ZrO2-2 prepared with the impregnation method (42.8% conversion and 16.2% alkane yield). The kinetics of octadecanol hydrotreatment revealed that the activation energy over 60%Ni–Fe/ZrO2 was much lower than Ni–Fe/ZrO2-2 (78.48 kJ/mol vs.191.90 kJ/mol). From the catalyst characterizations, the excellent performance of 60%Ni–Fe/ZrO2 was ascribed to its fine Ni particles, abundant Ni sites, high surface area, and coordinated acidity. Moreover, the mechanism of lipid deoxygenation over 60%Ni–Fe/ZrO2 was proposed.