Highly-efficient NiCo alloy catalysts towards hydrodeoxygenation of fatty acids to prepare alkanes

Abstract

Hydrodeoxygenation is a promising method for producing green diesel from fatty-acid-based biomass. Herein, we have reported NiCo alloy catalyst obtained by reduction of a layered double hydroxide (LDH) precursor, which displays prominent behavior for selective hydrodeoxygenation of fatty acids to prepare long-chain alkanes. The optimal Ni1Co1–600 shows catalytic performance (conversion: 99 %; alkanes selectivity: 97 %) in palmitic acid hydrodeoxygenation reaction, with milder conditions compared with previously reported studies on non-precious metal. A combination study including HR-TEM, XAFS and XPS confirms that a strong electron exchange occurs at the NiCo alloy catalys with electron transfer from Ni to Co in the metal. Both kinetic experiments and in situ FT-IR reveal the adsorption configuration of the substrate and the reaction pathway:Firstly, fatty acid is adsorbed at Ni-Co bimetallic sites through carboxyl group in the form of a bidentate bridge adsorption configuration; Then the active site is conducive to the process of decarbonylation of fatty alcohol intermediate to produce alkanes. This versatile catalytic system is poised to expand its applications to a wider array of reactions involving the breakdown of polar chemical bonds.