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Schematic drawing of Ni 12 P 5 and Ni formation on SiO 2 , ZSM-5 and Al 2 O 3 supports. [Display omitted] • Ni 12 P 5 crystal could effectively inhibit the coke formation on the catalysts. • High activity (95.4% conversion at 300 °C) was obtained on Ni 12 P 5 /SiO 2 catalyst. • Proper acidic sites and particle size of Ni 12 P 5 were responsible for high activity. Though nickel phosphides had been used widely to transform biomass into bio-fuel, the impact of support on the crystal formation was not clear. Herein, nickel and phosphides loaded on SiO 2 , ZSM-5 and γ-Al 2 O 3 were synthesized and the interaction between Ni/P and the supports was studied. Pure Ni 12 P 5 and pure Ni formed on SiO 2 and γ-Al 2 O 3 , respectively, whereas the mixture of Ni 12 P 5 and Ni formed on ZSM-5. The formation of AlPO 4 species was the main factor for the absence of Ni 12 P 5 on Ni/γ-Al 2 O 3 catalyst. Furthermore, the support also had a significant impact on the active phase with different particle size and dispersion, and further affected the performance. The highest fuel yield of 67.3 wt.% was obtained on Ni 12 P 5 /SiO 2 catalyst, which might be attributed to the appropriate acid sites and proper Ni 12 P 5 size. In addition, the catalysts with Ni 12 P 5 crystal phase displayed good resistance to coke deposition. The findings are important for clarification of the role of support in nickel phosphide active phase formation and coke deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • The coke resistance of Ni-based catalysts is improved profoundly by adding Er. • 99.3 % deoxygenation ratio and 64.7 % yield of biofuels is achieved on Ni-Er/50S-Al. • Er promotes the evenly distribution of Ni with smaller particle size. • More surface oxygen vacancies are critical for deoxygenating JO when REEs added. • The strong acidity leads to more coke form with Y added. Herein, three kinds of rare earth elements (Ce, Er and Y) were added to Ni-based catalysts to regulate the deoxygenation ability and coke resistance towards jatropha oil (JO) conversion. Among them, the catalysts with lanthanide metals (Ce and Er) added exhibit positive effects. Conversely, the addition of Y is counterproductive. The one with Er added displays the best catalytic performance, achieving the highest deoxygenation ratio (99.3 %) and product yield (64.7 %), and the resultant biofuel has the highest calorific value (46.02 MJ/kg). The stability of the Ni-Er/50S-Al catalyst is significantly improved due to the enhanced coke resistance compared with the one without Er added. Smaller Ni particle sizes with better dispersion, higher amount of surface Ni0 and surface oxygen vacancies are accomplished by adding Er, which contributes to the enhanced catalytic performance. The addition of Y weakens coke resistance, caused by strong acidity and big Ni particles. This study provides an effective idea for rationally designing catalysts with improved coke resistance and converting vegetable oils into biofuels. [ABSTRACT FROM AUTHOR]

Tungsten carbide-based materials have good deoxygenation activity in the conversion of biomass. In this paper, catalysts with different nickel–tungsten carbide species were prepared by tuning the reduction temperature and Ni loading, and the effects of these different tungsten carbide species in the conversion of jatropha oil were studied. XRD, XPS, TEM, HRTEM, Raman, H2-TPR, ICP-AES were used to characterize the catalysts. The results suggested that metallic W was gradually carburized to W2C species, and W2C species was further carburized to WC species with the increase in reduction temperature and Ni loading. The obtained 10Ni10W/AC-700 catalyst exhibited outstanding catalytic performance with 99.7% deoxygenation rate and 94.5% C15-18 selectivity, which were attributed to the smallest particle size, the best dispersion, the most exposed active sites, and the synergistic effect of Ni, W2C and WC species. [ABSTRACT FROM AUTHOR]

Although there is much work focused on the conversion of biomass oil into a fuel on bimetallic Ni‐ and Mo‐based catalysts, the intrinsic synergic effects of Ni and Mo have not been revealed clearly. Herein, Mo/Al‐MCM‐41, Ni/Al‐MCM‐41, and NiMo/Al‐MCM‐41 catalysts are synthesized and used for the catalytic conversion of jatropha oil into jet fuel through a one‐step process. The molecular weight range (150–180 Da) of the jet fuel, obtained with a high yield of 63 wt% over 10% NiMo/Al‐MCM‐41 catalyst, is almost the same as that of the commercial aviation fuel of China. A bimetallic catalyst shows not only an excellent activity but also a high carbon‐resistance nature compared with a monometallic catalyst. Characterizations using X‐ray diffraction, Raman spectroscopy, H2‐temperature‐programmed reduction, high‐angle annular dark‐field detector high‐resolution transmission electron microscopy (HADDF‐TEM)‐mapping, and in situ X‐ray photoelectron spectroscopy reveal that the formation of elliptical particles containing both Ni and Mo species and of appropriate acid sites with a proper density on the NiMo/Al‐MCM‐41 catalyst would result in a high yield of the jet fuel. Moreover, the electron transfer from Ni to Mo by a surface synergetic oxygen vacancy of Ni–Mo on the NiMo/Al‐MCM‐41 catalyst might be responsible for the excellent anti‐coke ability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-Mo 2 N catalyst can be effectively convert jatropha oil into high-quality biofuel. • The HDO performance of Ni-Mo 2 N is significantly improved than that of Mo 2 N. • The synergy of Ni and Mo 2 N assists in high biofuel yield and deoxygenation ability. • The interaction between metal and support would affect the deoxygenation pathway. Mo 2 N catalyst can effectively remove oxygen from biomass oil under harsh reaction conditions. Herein, the innovative Ni-Mo 2 N/γ-Al 2 O 3 catalyst was synthesized through conventional impregnation method and NH 3 or N 2 /H 2 pretreatment. The hydrodeoxygenation performance of Ni-Mo 2 N/γ-Al 2 O 3 catalyst is significantly improved in comparison with Mo 2 N. At 320 °C and 3 MPa, the oxygen of jatropha oil is completely removed and high-quality biofuel with high selectivity of C 15 -C 18 hydrocarbons are obtained over the Ni-Mo 2 N/γ-Al 2 O 3 catalyst. This good reactivity for Ni-Mo 2 N/γ-Al 2 O 3 catalyst are ascribed to the synergistic effect of Ni and Mo 2 N, the most uniform Ni dispersion and the excellent coke resistance ability. Ni, as an auxiliary, is conductive to the cleavage of H–H bonds, while Mo 2 N are beneficial to the cleavage of C–O bonds. In addition, the metal-support interaction would affect the deoxygenation pathway of jatropha oil. This research proposes an efficient strategy for enhancing the hydrodeoxygenation performance of Mo 2 N catalysts for the jatropha oil conversion. [ABSTRACT FROM AUTHOR]