Synthesis of Pt-based TS-1 catalysts for selective hydrogenation to produce C15–C18 alkanes from the FAME: Effect of rare-earth metal additives

Green biodiesel is a clean, renewable, and environmental-friendly biofuel, which is commonly produced through catalytic conversion of lipids. The properties of Pt-based catalyst carriers and additives are important factors determining the production of green biodiesel. Herein, titanium silicalite-1 (TS-1) with a large specific surface area was synthesized by a hydrothermal crystallization process, and the rare-earth metal additives including LaOx, CeOx, PrOx, and YOx were used to modify Pt/TS-1 on the fatty acid methyl ester (FAME) hydrotreatment to enhance the selectivity of C15–C18 alkanes. It is shown that the addition of rare-earth metals decreases the particle size of Pt, increases the content of Pt0 species, and changes the major reaction pathway from hydrodecarbonylation (DCO)/hydrodecarboxylation (DCO2) to hydrodeoxygenation (HDO). The Pt–Ce/TS-1 showed the best catalytic performance on the FAME hydrotreatment due to its smaller active metal particle size, more amounts of weak acid, abundant oxygen vacancies, and more content of low chemical states of Pt. The liquid yield, efficiency of deoxygenation, and selectivity of C15–C18 alkanes were 75.7%, 100%, and 97.3% over Pt–Ce/TS-1. The heating value of upgraded liquid products from Pt–Ce/TS-1 reached 49.1 MJ/kg. This work provides a new idea for Pt-based TS-1 catalysts in the preparation of green hydrocarbon biodiesel.