The influences of the distance between the hydrogenation center and cracking center and diffusivities of catalysts on hydrocracking behaviors were investigated. It was initially found that, compared with the catalysts with only micromeso-Y zeolite or meso-AlO, the diffusivities of combined catalysts with both Y zeolite and AlO could be significantly improved. The NiW/Y-A catalyst presents the best diffusivity due to the introduction of pure meso-AlO. The property of active metals and acidity play an important role on the adsorption ability of catalyst. The n-dodecane hydrocracking results showed that the NiW/Y-A catalyst with the lowest dispersion degree of metals, acidity and proportion of active WS phase presented the highest activity due to its superior diffusivity. The results also revealed that a closer distance between the hydrogenation and cracking centers leads to a higher selectivity of iso-cracking, liquid yield and better stability of catalysts. The above findings provide a potential novel method for designing catalysts with high activities and selectivities.

中文翻译：

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高效转化碳氢化合物的双功能催化剂：增强微孔和中孔之间的扩散

考察了加氢中心与裂化中心的距离以及催化剂的扩散系数对加氢裂化行为的影响。初步发现，与仅含有微介观-Y沸石或介观-Al2O的催化剂相比，同时含有Y沸石和Al2O的组合催化剂的扩散率可以得到显着提高。由于引入了纯内消旋 Al2O，NiW/YA 催化剂呈现出最佳的扩散性。活性金属的性质和酸度对催化剂的吸附能力起着重要作用。正十二烷加氢裂化结果表明，金属分散度、酸性和活性WS相比例最低的NiW/YA催化剂由于其优异的扩散性而表现出最高的活性。结果还表明，加氢中心和裂化中心之间的距离越近，异构裂化的选择性越高，液体产率越高，催化剂的稳定性越好。上述发现为设计具有高活性和选择性的催化剂提供了一种潜在的新方法。