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.

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An in situ encapsulation process was used to prepare ordered worm-like mesoporous Pt@SAPO-11 catalysts with different Pt loadings. Transmission electron microscopy images showed that Pt nanoparticles encapsulated within the SAPO-11 support mesopores were uniformly distributed and highly dispersed and had a narrow particle size distribution of 2–7 nm. Scanning electron microscopy indicated that increasing the Pt loading from 0.6 to 1.6 wt % did not significantly change the crystalline morphology of the catalyst, although the crystallinity decreased slightly. The specific surface area and average pore diameter of the Pt@SAPO-11 were in the ranges of 72–116 m2/g and 8.1–9.5 nm, respectively, which are determined by the Brunauer–Emmett–Teller method and Barrett–Joyner–Halenda method, respectively. The NH3 thermal-programmed desorption established that increasing the Pt loading gradually decreased the total NH3 desorption and that a loading of 1.2 wt % produced the highest concentration of medium-strong acid sites (6.2 cm3/g STP). X-ray photoelectron spectroscopy and H2 temperature-programmed reduction showed that a Pt loading of 1.2 wt % gave the strongest interaction between Pt nanoparticles and the SAPO-11 support. The Pt@SAPO-11 catalysts were used for the preparation of C8–C17 alkanes by decarboxylation of oleic acid. Employing a reaction temperature of 340 °C, a CO2 atmosphere, a Pt loading on the catalyst of 1.2 wt %, and a reaction time of 4 h, 100% oleic acid conversion was obtained together with an 80% yield of C8–C17 alkanes.