苯中硫在Ni/ZnO催化剂上加氢吸附脱除的研究

比较了浸渍法与共沉淀法制备的Ni/ZnO催化剂对芳烃原料的深度脱硫活性和选择性，并采用H₂-TPR、XRD和BET等手段对催化剂进行了表征。结果表明，NiO与载体ZnO之间的相互作用程度对催化剂的性能有很大影响。与ZnO相互作用较弱的游离态NiO还原后生成的Ni⁰，导致苯加氢生成环己烷；与ZnO相互作用较强的NiO还原后生成的Ni⁰具有脱硫能力但不是苯加氢活性中心。共沉淀法制备的催化剂由于NiO与载体相互作用较强，游离态NiO较少，且比表面积相对较大，因而具有较高的活性和选择性。同时发现，还原温度对催化剂的性能具有很大影响，在400℃还原时开始出现Ni_xZn_y合金，且随着还原温度的升高，晶粒长大，比表面积降低，导致催化剂活性降低。Sn助剂的加入能增加NiO与载体的相互作用，抑制游离态的NiO生成，从而减少苯的损失。

Ultra-deep hydrodesulfurization of benzene over Ni/ZnO catalyst

Ni/ZnO catalyst prepared by impregnation and co-precipitation methods for ultra-deep hydrodesulfurization of benzene was studied. The structures and properties of the catalysts were investigated by H_2-TPR, XRD and BET techniques. It was found that the interaction between NiO and ZnO has important influence on the activity and selectivity of the catalysts. NiO with weak interaction with ZnO has high benzene hydrogenation activity after reduction by H_2, resulting in conversion of benzene to cyclohexane, whereas, NiO with strong interaction with ZnO has hydrodesulfurization activity, but has no benzene hydrogenation activity. The catalysts prepared by impregnation showed certain content of weak-interaction NiO, so the benzene exhibited great lose. The NiO, prepared by co-precipitation, has strong interaction with ZnO,so the catalyst has better selectivity toward desulfurization. Furthermore, the catalyst prepared by co-precipitation had a higher BET area. As a result, the activity and selectivity were higher over catalyst prepared with co-precipitation than that over catalyst prepared by impregnation. It was found that reduction temperature has important influence on catalyst activity and selectivity. Catalyst reduced at 400℃showed the best performance while reduction at 500℃ resulted in the decrease of the activity due to crystal particles sintering and specific surface area decrease. Addition of Sn can change the interaction between NiO and ZnO. Due to the inhibition of formation of weak-interaction NiO, Sn addition suppressed greatly the loss of benzene.