Selective Hydroconversion of Oleic Acid into Aviation-Fuel-Range Alkanes over Ultrathin Ni/ZSM-5 Nanosheets

Abstract

Ultrathin Ni/ZSM-5 nanosheet catalysts with different acid concentrations, B/L (Brønsted/Lewis acid sites) ratios, and nanosheet thicknesses are designed for the hydroconversion of oleic acid into aviation-fuel-range alkanes (AFRAs). The role of acid concentration/distribution and nanosheet thickness was investigated. High acid concentration enhances the hydrodeoxygenation (HDO) reaction and intrinsic deoxygenation activity because of the synergistic effect between acid sites and metal sites. The selective cracking reaction can be enhanced by tailoring nanosheet thickness and acid distribution. The thin nanosheet favors isomerization, the selective cracking reaction, as well as the generation of central branched isomers. External acid sites dominate the primary cracking and central C−C cracking of the deoxygenated products, but internal acid sites promote the deeper cracking and terminal C−C cracking. Formation of aromatics is thoroughly suppressed at low reaction temperature (≤533 K). A high AFRA yield of 41.4% is achieved over the 3 nm nanosheet catalyst with Si/Al = 300 and B/L = 0.18.

Hollow Hierarchical Silicalite-1 Zeolite Encapsulated PtNi Bimetals for Selective Hydroconversion of Methyl Stearate into Aviation Fuel Range Alkanes

“…The maximal aviation fuel selectivity of 45% was acquired at 360 °C. However, the selectivity reduced to 31% at elevated temperatures owing to the secondary cracking of C 9 –C 15 alkanes (up to 66%) . PtNi@HS-1 possessed fewer acid sites but with higher catalytic performance compared to the PtNi/S-1 catalyst; the discrepancy in product distribution for these two catalysts is ascribed to the hollow encapsulated structure.…”

“…However, the selectivity reduced to 31% at elevated temperatures owing to the secondary cracking of C 9 − C 15 alkanes (up to 66%). 67 PtNi@HS-1 possessed fewer acid sites but with higher catalytic performance compared to the PtNi/S-1 catalyst; the discrepancy in product distribution for these two catalysts is ascribed to the hollow encapsulated structure. Based on the results of FE-TEM, XPS, and ICP− OES, the active metals in the PtNi@HS-1 catalyst are mainly located in the cavities with a shell thickness of around 20 nm.…”

Insight into the Selection of the Post-Treatment Strategy for ZSM-5 Zeolites for the Improvement of Catalytic Stability in the Conversion of Methanol to Hydrocarbons

“…Py-IR spectra were recorded at a desorption temperature of 200 °C and the results are shown in Figure . The two peaks at around 1454 and 1545 cm –1 were attributed to LASs and BASs, respectively . After the Gaussian function fitting and integration of spectra, the content of LASs and BASs for these samplesis summarized in Table .…”

“…The two peaks at around 1454 and 1545 cm −1 were attributed to LASs and BASs, respectively. 37 After the Gaussian function fitting and integration of spectra, the content of LASs and BASs for these samplesis summarized in Table 4. The amount of BASs and LASs of Z was 0.044 and 0.012 mmol g −1 , respectively.…”

Alkane Production from Unsaturated Fatty Acids over Transition Metal‐Doped Pd Catalysts

“…The second factor is the catalyst type. It was shown that transition metal catalysts result in HDO or DO processes [14][15][16][17][18][19][20][21][22]. In some studies, DCN was mentioned as an unconventional pathway for fatty acid conversion to hydrocarbons over transition metal catalysts [23,24].…”