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

Abstract

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.

CuO@NiO Nanoparticles Derived from Metal–Organic Framework Precursors for the Deoxygenation of Fatty Acids

“…Toward this end, noble-metal catalysts, such as Pt, − Pd, Ru, , and Rh, have been widely studied in-depth for green diesel production. However, their high cost remains a great obstacle to industrial application.…”

Decarboxylation of Oleic Acid Using Pt@SAPO-11 Catalysts Fabricated by In Situ Encapsulation

“…33 The morphologies of these samples were also close to those of Pt/SAPO-11 prepared by deposition precipitation in our previous work. 28 As the Pt loading was increased, the crystal morphology of the Pt@SAPO-11 did not undergo any obvious changes, although the degree of crystallinity decreased slightly.…”

“…This result indicates that the mesoporous structure of the SAPO-11 was well preserved after Pt incorporation and that the amount of Pt loaded did not change the mesoporous structure of the sample. 28 As the Pt loading was increased, the amount of nitrogen adsorption decreased, which may have been caused by the increased density of Pt nanoparticles encapsulated within the mesopores of the SAPO-11 support. 33 The insets to these figures show the pore diameter distributions of the samples, which confirm that each material was mesoporous with pore diameters primarily in the range of approximately 8− 10 nm.…”

“…The mesoporous structure, in turn, enhanced the diffusion of oleic acid through the zeolite channels, thereby remarkably improving the catalytic activity. In our own previous work, 28 SAPO-11 molecular sieves with ordered mesoporous structures were synthesized using a hydrothermal method with a poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) (PEO− PPO−PEO) triblock copolymer as the structure-directing agent. The Pt/SAPO-11 catalysts were subsequently prepared by a deposition−precipitation method and applied to the DCO 2 of oleic acid to give yields of C 8 −C 17 alkanes as high as 78%.…”

“…29−31 To overcome this issue, some researchers have used in situ encapsulation to synthesize metal nanoparticle catalysts exhibiting a high degree of dispersion and good stability. 10,28,30 As an example, Bian et al 20 synthesized ordered mesoporous Fe 2 O 3 /MCM-41 and Fe 2 O 3 /Al-MCM-41 catalysts by in situ encapsulation and applied these materials to the DCO 2 of palmitic acid. These materials were found to have pore sizes of 2.5 and 2.6 nm, respectively, and the Fe 2 O 3 particles were determined to be MCM-41 was used, pentadecane was the main product, although C 8 −C 14 and other products were also generated.…”