Catalytic Deoxygenation of Oleic Acid and Oils into a Gasoline-Range Hydrocarbon over a Highly Efficient La-Based Al-SAPO-11 Catalyst: A Combined Experimental and DFT Calculation

Selective catalytic deoxygenation of waste vegetable oil with a non-noble-metal catalyst into a gasoline-range hydrocarbon faces the central challenge of a lower catalytic hydrodeoxygenation activity and lower desirable product yield. Here, a series of highly efficient and durable La-based Al-SAPO-11 catalysts were developed and applied to catalytic oleic pyrolysis into gasoline. Additionally, the catalytic mechanism was also elucidated by DFT calculations. Detailed experimental and characterization results revealed that La–Ni codoped catalysts exhibited excellent activity in the catalytic cracking of oleic acid into a gasoline fraction, achieving a hydrocarbon yield of up to 95.28% and a gasoline selectivity of 91.22%. Furthermore, La–Ni/AS also exhibited excellent applicability and reusability, recycling over four times, with a significant potential for industrial hydrocarbon fuel production, due to the synergistic effect of decarbonylation and hydrodeoxygenation reactions, as well as the ternary synergy between the uniformly dispersed Ni⁰ metal sites, higher oxygen vacancies (La³⁺-Ov-Ni²⁺), and Lewis acids. Oxygen vacancies derived from Ni species at the metal–support interface induced the La dissociation of H₂ and adsorbed/activated carbonyl group for the hydrodeoxygenation reaction, and La species with enhanced Lewis acidity promoted the well dispersion of Ni species and OA cracking reaction. Both experimental and density functional theory (DFT) computational studies confirmed the synergistic effect derived from Ni and La active sites intimately contacting and inhibiting active metallic species leaching and agglomeration, enhanced C–C cleavage, and inhibition of the aromatization reaction induced by the isolated single-metal Ni site.