已经探索了赤泥负载的 Ni (Ni/RM) 催化剂用于棕榈酸的加氢脱氧 (HDO),然而,脱羰基化 (DCO)/脱羧 (DCO2) 占主导地位。因此,催化剂亲氧性质的改性会显著影响其 HDO 路径和对目标产物的选择性。在此,制备了具有多级花状微/纳米结构的 MoOx 修饰的 Ni-Mo/RM 催化剂,并将其应用于棕榈酸的 HDO。研究了 MoOx 添加对 HDO 路径的控制作用,导致产物碳数分布的变化。结合几个全面的结构表征和催化 HDO 测试,表明表面缺陷的 MoOx 种类和金属位点附近的 FeOx 种类可以显着促进 C-O 键的弱化,产生更直接的脱氧产物(十六烷)。而过量的 Mo 负载导致表面化学性质的明显改变(即比表面积、孔体积和 Mo0 种类的减少、还原温度和 CO2 吸附的增加、Ni 种类的分散不均匀和团聚),导致棕榈酸转化率降低。作为 RM 中的主要氧化物,Fe2O3、Al2O3 和 SiO2 分别以 Fe2O3、Al2O3 和 SiO2 为载体负载 Ni-Mo 双金属,探究 RM 中不同组分对棕榈酸加氢脱氧产物分布的贡献。
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Rationally control the path of hydrodeoxygenation of palmitic acid over Ni/red-mud catalysts by surface decoration of oxophilic MoOx species
Red mud supported Ni (Ni/RM) catalysts have been explored to the hydrodeoxygenation (HDO) of palmitic acid, however, the decarbonylation (DCO)/decarboxylation (DCO2) is dominant. Therefore, the modification the oxophilic nature of catalysts can significantly impact their path of HDO and selectivity to aim products. Herein, MoOx-decorated Ni-Mo/RM catalysts with a hierarchical flower-like micro/nanostructure were prepared and applied in the HDO of palmitic acid. The effect of MoOx addition was investigated to control the path of HDO, resulting in the changing of carbon number distribution of the product. Combined with several comprehensive structural characterizations and catalytic HDO test, it is shown that the surface defective MoOx species and FeOx species near the metallic sites could significantly facilitate the C-O bond weakening, generated more direct deoxygenation product (hexadecane). Whereas the excessive Mo loading leads to clear altering of surface chemistry (i.e., decrease of specific surface area, pore volume and Mo0 species, increase of reduction temperature and CO2 adsorption, uneven dispersion, and agglomeration of Ni species), resulting in the decrease of palmitic acid conversion. As the main oxide in RM, Fe2O3, Al2O3 and SiO2 were used as supports to load Ni-Mo bimetals respectively to explore the contribution of different components in RM to the distribution of hydrodeoxygenation products of palmitic acid.