镍含量对超细粒子负载型催化剂性能的影响——镍含量调变对NiO/SiO_2-TiO_2性能的影响

Effect of NiO Content on the Ultrofine Support Catalytic Performance ——Effect of NiO Content on the Catalytic Performance of NiO/SiO 2 TiO 2

用溶胶－凝胶法，制备了不同镍含量的镍基超细粒子负载型催化剂前体ＮｉＯ／ＳｉＯ２－ＴｉＯ２．用氨溶－原子吸收分光光度法、ＴＰＲ技术，考察了活性组分氧化镍与载体之间的相互作用；通过ＩＲ、ＸＲＤ、ＴＥＭ－ＥＤＳ等手段，研究它们的物化性质、结构特征．用加压固定床连续流动微反装置上苯加氢生成环己烷的反应，对它们的催化性能进行关联．实验结果表明，采用溶胶－凝胶法制备得到的镍基超细粒子负载型催化剂体系中，活性组分氧化镍与载体之间有较强的相互作用，氧化镍形成簇状微晶，均匀地分散在载体氧化物之中．镍含量的调变，影响体系中氧化镍的微晶尺寸及其与载体的相互作用．催化剂在低镍含量（ＮｉＯ≥８％）时，即显出很高的活性，并具有优良的热稳定性及很宽的反应活性温度区域（１２０～２８０℃）．

NiO/SiO 2 TiO 2 catalyst precursors with different NiO content were prepared by means of sol gel method, the interaction of active component NiO and support SiO 2 TiO 2 were determined by AAS (Ammonia dissolved substance test )and TPR, the physical and chemical properties and structure of these catalysts were examined by IR、 XRD、 TEM EDS and BET methods. The heat resistance and the ability of anti poisoning of the catalysts were studied. The results show that the interaction between NiO and SiO 2 TiO 2 was very strong. The NiO crystallite clusters disperse uniformly in the support, and NiO particle sizes increase a little with the increasing of NiO content. These catalysts have very high hydrogenation activity (benzene conversion up to 100%)and high selectivity to cyclohexane (greater than 99.8%) even at low NiO content (NiO>8%). They show good heat resistance, can be performed in a wide reaction temperature area ranged from 120 ℃ to 280 ℃.