This research work aimed to investigate the performance of unsupported and γ-Al₂O₃ supported nickel–molybdenum (Ni–Mo) catalysts for palm oil deoxygenation to biohydrogenated diesel. Three preparation methods of supported catalyst (one-step hydrothermal, physical mixing, and incipient wetness impregnation) were studied. In all experiments, the main products were n-alkanes (n-C₁₄, n-C₁₅, n-C₁₆, n-C₁₇, and n-C₁₈). For palm oil deoxygenation over an unsupported NiMoS₂ catalyst, increasing the palm oil concentration enhanced the decarbonylation (DCO) and decarboxylation (DCO₂) pathways, while prolonging the reaction time led to an increased relative rate of hydrodeoxygenation (HDO) rather than DCO and DCO₂ reactions. The unsupported 0.2-NiMoS₂ catalyst (at a Ni/[Ni + Mo] molar ratio of 2) prepared by a hydrothermal method was the efficient catalyst, while the appropriate reaction conditions were 300 °C for 3 h at an initial hydrogen pressure of 40 bar, with a catalyst/palm oil ratio of 0.1, to give the highest C_14–18 alkane yield of 67.0 wt %. The selectivities for n-C₁₅, n-C₁₆, n-C₁₇, and n-C₁₈ alkanes were 19.6%, 20.2%, 26.8%, and 33.0%, respectively. A new supported NiMoS₂ catalyst prepared by a one-step hydrothermal method was proposed. This technique merges the advantages of both an alumina (Al₂O₃) support and our previous hydrothermal method. The H-NiMoS₂/γ-Al₂O₃ supported catalyst with a 20 wt % Al₂O₃ loading (H-NiMoS₂/γ-Al₂O₃-0.2) prepared by the hydrothermal method presented a higher dispersion of Ni–Mo–S species than the unsupported catalyst, which results from the Al₂O₃ support. Without needing further presulfidation, the H-NiMoS₂/γ-Al₂O₃-0.2 catalyst showed good HDO activity under appropriate conditions, which gave a high C_14–18 yield of 55.4 wt % and a selectivities for n-C₁₅, n-C₁₆, n-C₁₇, and n-C₁₈ of 14.1%, 25.3%, 19.7%, and 36.3%, respectively. The 0.2-NiMoS₂ and H-NiMoS₂/γ-Al₂O₃-0.2 catalysts could be reused for at least three cycles of deoxygenation while maintaining a good performance.

中文翻译：

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在无负载和 γ-Al2O3 负载的 Ni-Mo 催化剂上从棕榈油脱氧得到的生物氢化柴油

本研究工作旨在研究未负载和 γ-Al ₂ O ₃负载的镍钼 (Ni-Mo) 催化剂在棕榈油脱氧为生物加氢柴油中的性能。研究了三种负载型催化剂的制备方法（一步水热法、物理混合法和初湿浸渍法）。在所有实验中，主要产物为正构烷烃（n -C ₁₄、n -C ₁₅、n -C ₁₆、n -C ₁₇和n -C ₁₈）。用于无载体 NiMoS _{2 上的}棕榈油脱氧催化剂，增加棕榈油浓度增强了脱羰 (DCO) 和脱羧 (DCO ₂ ) 途径，同时延长反应时间导致加氢脱氧 (HDO) 的相对速率增加，而不是 DCO 和 DCO ₂反应。水热法制备的无载体0.2-NiMoS ₂催化剂（Ni/[Ni + Mo]摩尔比为2）是有效的催化剂，而合适的反应条件是300℃，初始氢气压力为3h。 40 bar，催化剂/棕榈油比为 0.1，得到最高的 C _14-18烷烃产率 67.0 wt%。n -C ₁₅ , n -C ₁₆ , n的选择性-C ₁₇和n -C ₁₈烷烃分别为19.6%、20.2%、26.8%和33.0%。提出了一种采用一步水热法制备的新型负载型NiMoS ₂催化剂。这种技术结合了氧化铝 (Al ₂ O ₃ ) 载体和我们以前的水热方法的优点。H-NiMoS ₂ /γ-Al ₂ O ₃负载为 20 wt% Al ₂ O _{3 的}催化剂（H-NiMoS ₂ /γ-Al ₂ O ₃-0.2) 通过水热法制备的 Ni-Mo-S 物种比未负载的催化剂具有更高的分散性，这是由 Al ₂ O ₃载体产生的。无需进一步预硫化，H-NiMoS ₂ /γ-Al ₂ O ₃ -0.2 催化剂在适当条件下表现出良好的 HDO 活性，C _14-18产率高达 55.4 wt%，对n -C ₁₅具有选择性，n -C ₁₆、n -C ₁₇和n -C _{18 分别}为14.1%、25.3%、19.7%和36.3%。0.2-NiMoS ₂H-NiMoS ₂ /γ-Al ₂ O ₃ -0.2 催化剂可以重复使用至少三个脱氧循环，同时保持良好的性能。