Supported Ru–Zn/ZrO₂ catalysts are successfully prepared by a two-step impregnation method (Zn deposition–calcination–Ru deposition), and their catalytic performances for selective liquid-phase hydrogenation of benzene are investigated. Physical properties of the catalysts are characterized by N₂ adsorption, atomic absorption spectroscopy, X-ray diffraction, temperature-programmed reduction, transmission electron micrographs, dynamic light scattering and X-ray photoelectron spectroscopy. Effects of the Zn content, concentration of alkaline treatment (NaOH) after hydrogen reduction, and hydrogen reduction temperature on the properties of Ru–Zn/ZrO₂ catalysts with a fix Ru loading of 10.0 wt% are studied. It is found that the optimal ZnO content is 10.5 wt% in the first-step impregnation (ZnO–ZrO₂), and that the alkaline treatment after hydrogen reduction is very important for obtaining the optimal Zn content in the ultimate catalyst. Over the optimal Ru–Zn/ZrO₂ catalyst with 10.0 wt% Ru and 2.78 wt% Zn, the selectivity to cyclohexene can reach 80% at the benzene conversion of 50% under the reaction condition (1200 r/min, 150 °C, 5 MPa H₂). The specific activity of the catalyst is about 4 times higher than those of Ru–Zn catalysts prepared by coprecipitation. The recycle catalytic performance of the optimal Ru–Zn/ZrO₂ catalyst is also explored. There is no significant decrease of catalytic performance after four recycles, indicating good stability of the catalyst prepared by the two-step impregnation method.

中文翻译：

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两步浸渍法制备的Ru-Zn / ZrO ₂催化剂上苯选择性加氢成环己烯

通过两步浸渍法（Zn沉积-煅烧-Ru沉积）成功制备了负载型Ru-Zn / ZrO ₂催化剂，并研究了它们对苯选择性液相加氢的催化性能。催化剂的物理性质通过N ₂吸附，原子吸收光谱，X射线衍射，程序升温还原，透射电子显微照片，动态光散射和X射线光电子能谱来表征。Zn含量，氢还原后碱处理浓度（NaOH）和氢还原温度对Ru–Zn / ZrO _{2性质的影响}研究了固定Ru负载量为10.0 wt％的催化剂。发现第一步浸渍（ZnO–ZrO ₂）的最佳ZnO含量为10.5 wt％，氢还原后的碱处理对于最终催化剂中获得最佳Zn含量非常重要。在具有10.0 wt％的Ru和2.78 wt％的Zn的最佳Ru-Zn / ZrO ₂催化剂上，在反应条件下（1200 r / min，150°C， 5 MPa H ₂）。该催化剂的比活度是通过共沉淀制备的Ru-Zn催化剂的比活度的约4倍。最佳Ru–Zn / ZrO ₂的循环催化性能还探索了催化剂。在四个循环后，催化性能没有显着降低，表明通过两步浸渍法制备的催化剂具有良好的稳定性。