Decarboxylation of Oleic Acid over Ordered Mesoporous Pt/SAPO-11

Ordered mesoporous SAPO-11 molecular sieves (OMSMS) with a single mesoporous structure were prepared via a one-step hydrothermal method. Metal–acid bifunctional Pt/SAPO-11 (Pt/OMSMS-700) catalysts with Pt loadings of 1% and 2% were synthesized by a deposition–precipitation method using OMSMS-700 as a carrier. The OMSMS and Pt/OMSMS-700 were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (N2 -BET) analysis, and X-ray powder diffraction (XRD). TEM and small-angle XRD results revealed that the degree of order in the OMSMS increased as the calcination temperature increased from 500 to 700 °C. The N2 -BET analysis revealed that the OMSMS had a mesoporous structure with an average pore diameter of 6.4–7.8 nm and a BET surface area of 149–171 m2/g. The sizes of the Pt nanoparticles supported on OMSMS-700 were in the range of 3 to 6 nm and displayed good dispersibility. The catalytic performance of Pt/OMSMS-700 during the decarboxylation of oleic acid to form C8–C17 alkanes under a CO2 atmosphere was investigated. As the reaction temperature increased from 320 to 360 °C, the total yield of C8–C17 alkanes initially increased and then decreased. Increasing the Pt loading led to an increased yield of C8–C17 alkanes. The total yield of C8–C17 alkanes reached 78% when 2 wt % Pt/OMSMS-700 was used at 340 °C for 3 h.