Bifunctional CuNi/CoOx catalyst for mild-temperature in situ hydrodeoxygenation of fatty acids to alkanes using isopropanol as hydrogen source

Bifunctional CumNin/CoOx catalysts were fabricated by co-precipitation method and applied in in-situ hydrodeoxygenation (HDO) of biomass derived oleic acid to n-heptadecane with isopropanol as hydrogen source. Upon incorporating Cu or Ni into CoOx, the catalytic performance could be easily boosted. By varying Cu/Ni ratio, reduction temperature as well as catalyst loading, the optimized Cu1Ni1/CoOx exhibited >99% conversion and 91.3% n-heptadecane yield at 240 degrees C in 8 h. Characterizations showed that synergistic effect between Cu, Ni and CoOx was existed, thus strengthening H-2 production ability towards isopropanol and favoring the generation of n-heptadecane. Kinetic studies revealed HDO of oleic acid to alkane mainly proceeded via decarbonylation of stearaldehyde rather than direct decarboxylation of stearic acid, and the rate determining step relied on octadecanol dehydrogenation. This catalyst could be magnetically separated for 5 times recycling and was versatile for in situ HDO of various fatty acids, thus achieving a low-cost, energy-saving biomass-to-biofuel conversion.