Fabrication of a NiFe Alloy Oxide Catalyst via Surface Reconstruction for Selective Hydrodeoxygenation of Fatty Acid to Fatty Alcohol

Traditional NiFe alloy catalyst (NiFe AC) possesses low alcohol selectivity for the hydrodeoxygenation (HDO) of fatty acid due to its excessive deoxygenation into alkane. Herein, we innovatively provide the NiFe alloy oxide catalyst (NiFe AOC) to suppress the adsorption of aldehyde, which is the crucial intermediate of objective product alcohol converting into a side product, via the steric hindrance of lattice oxygen to inhibit the further conversion of alcohol. NiFe AOC reaches 100% conversion of lauric acid with 90% selectivity to lauryl alcohol. Kinetic analysis indicated that the apparent activation energy of side reaction increases by 71.1 kJ/mol for NiFe AOC relative to NiFe AC, evidencing the inhibition for the conversion of objective product alcohol into alkane for NiFe AOC. Furthermore, DFT calculation also suggests that the activation energy of the side reaction increases by 0.33 eV on NiFe AOC compared to NiFe AC. In addition, used NiFe AOC can be totally regenerated via surface reconstruction during the reduction-reoxidation treatment. However, overoxidation inducing NiFe surface phase separation weakened the synergistic interaction of Ni-Fe bimetallic sites and further decreased the catalytic activity.

Automated summary

The study introduces a novel NiFe alloy oxide catalyst (NiFe AOC) that effectively suppresses the adsorption of aldehyde, leading to improved alcohol selectivity and yield in the hydrodeoxygenation of fatty acids. NiFe AOC demonstrates inhibition of the conversion of objective product alcohol into alkane, with increased activation energy for side reactions compared to NiFe AC.