Synthesis of mesoporous Pt@KIT-6/SAPO-11 VIA in situ encapsulation to catalyze the decarboxylation of oleic acid to C8-C17 alkanes

BACKGROUND: A series of mesoporous Pt@KIT-6/SAPO-11 catalysts with SiO2:Al2O3 molar ratios of 0.3, 0.4, or 0.5 and Pt loadings of 0.4, 0.8, or 1.2 wt% were prepared via an in situ encapsulation process using a PEO - PPO - PEO triblock copolymer (EO20PO70EO20, P123) as the mes. China 750001 oporous template and KIT-6 molecular sieves as the silicon source. RESULTS: These catalysts were characterized by transmission electron microscopy (TEM), specific surface area analysis, and pyridine-infrared spectroscopy (Py - IR). The results showed that Pt nanoparticles with particle sizes of 3-7 nmwere uniformly dispersed on the supports. These materials also exhibited good mesoporous structures with specific surface areas of 138-197 m(2)/g and average pore sizes of 7.1-9.9 nm. The specimens having a SiO2:Al2O3 molar ratio of 0.4 also showed an orderly strip-shaped pore structure. The Py - IR results indicated that the catalysts had both Bronsted acid and Lewis acid sites, with total acid contents in the range of 77.8-131.1 mu mol/g. CONCLUSION: The decarboxylation of oleic acid using these materials under CO2 was examined. The catalyst with a SiO2:Al2O3 molar ratio of 0.4 and a Pt loading of 0.8 exhibited the best catalytic performance and a C8 - C17 alkanes yield as high as 85.1% at 340 degrees C by using a catalyst-to-oil mass ratio of 1:10 and a reaction time of 5 h. This performance was attributed to the ordered mesoporous structure of this catalyst along with its high surface area (173 m(2)/g), good crystallinity (92.8%), suitable acid content (98.6 mu mol/g), and abundant Pt metal active sites. (c) 2022 Society of Chemical Industry (SCI).