ZnO载体的形貌对Ni/ZnO催化剂脱硫性能和再生性能的影响

Ni/ZnO脱硫催化剂由于其脱硫精度高，辛烷值损失小而被广泛关注。但是在脱硫过程中存在ZnO易于失活、活性组分Ni易于团聚等问题，进而影响了催化剂的使用性能。为了克服这些问题，载体ZnO的改性被广泛研究，然而关于载体ZnO的形貌和粒子尺寸对催化剂性能以及活性组分Ni的分散程度的影响却报道较少。本文通过控制碱浓度分别合成了粒状、短棒状和纳米线状ZnO，并以其为载体，负载金属镍后，制备成脱硫催化剂，通过X射线衍射，N2吸附-脱附，SEM，TEM等方法对催化剂进行了表征；并以正庚烷-噻吩为模型化合物，考察了其脱硫性能。结果表明the morphology , and size of ZnO support对催化剂的脱硫性能具有很大的影响，以线状形貌的ZnO为载体制备的脱硫催化剂具有最好的脱硫性能，其脱硫率高达98.2%，这主要是由于ZnO载体的线状结构有效抑制了表面Ni原子的团聚，降低了金属活性组分镍的粒子尺寸，提高了其在载体表面的分散度；同时纳米线状结构减小了噻吩在反应过程中的扩散阻力，提供了有利于硫转移和扩散的通道，因而使其在脱硫反应过程和再生性过程中具有了良好的性能。

The Effect of the Morphology of ZnO Support on the Desulfurization and Regeneration Performance of Ni/ZnO Catalyst

Ni/ZnO desulfurization catalyst has been widely concerned for its high desulfurization rate and low octane value loss. However, during the process of desulfurization, ZnO was easy to deactivate and the active component Ni was easy to agglomerate, which affected the performance of the catalyst. In order to solve these problems, the modification of ZnO support has been extensively studied. However, there are few reports on the effect of the morphology and particle size of ZnO support on the performance of Catalyst and the dispersion degree of the active component Ni. In this paper, granular, short rod-shaped and nanowires ZnO were synthesized by controlling the concentration of NaOH, and the desulfurization catalyst was prepared with ZnO as the support after loading of metallic Ni. The catalyst was characterized by X-ray diffraction, N2 adsorption-desorption, SEM, TEM and other methods. The desulfurization performance of the catalyst was investigated with n-heptane - thiophene as model compound. Results showed that the morphology and size of ZnO support has great influence on the desulphurization performance of the catalyst. Desulfurization catalyst prepared with nanowires ZnO support has the best desulfurization performance and its desulfurization rate can reach at 98.2%. It was mainly due to the nanowires structure of ZnO support can effectively restrain the agglomeration of metallic Ni in the surface and reduce the particle size of the active component of metallic Ni so as to improve its dispersion in the surface of the support. In addition, the nanowires structure can reduce the diffusion resistance of thiophene in the reaction process and provide a channel conducive to sulfur transfer and diffusion, which makes it performs well in the desulphurization reaction process and regeneration process. Key Words: ZnO; morphology; nanowires; desulphurization; regeneration