Stabilizing Catalytic Pathways via Redundancy: Selective Reduction of Microalgae Oil to Alkanes

Abstract

A new route to convert crude microalgae oils using ZrO₂-promoted Ni catalysts into diesel-range alkanes in a cascade reaction is presented. Ni nanoparticles catalyze the selective cleavage of the C–O of fatty acid esters, leading to the hydrogenolysis of triglycerides. Hydrogenation of the resulting fatty acids to aldehydes (rate-determining step) is uniquely catalyzed via two parallel pathways, one via aldehyde formation on metallic Ni and the second via a synergistic action by Ni and ZrO₂ through adsorbing the carboxylic groups at the oxygen vacancies of ZrO₂ to form carboxylates and subsequently abstracting the α-hydrogen atom to produce ketene, which is in turn hydrogenated to aldehydes and decarbonylated on Ni nanoparticles