新型Ni/TiO_2催化剂用于对硝基苯酚催化加氢

p-Nitrophenol Hydrogenation over a Novel Ni/TiO_2 Catalyst

以介孔氧化钛晶须为载体,采用等体积浸渍法制备了Ni/TiO2催化剂,通过扫描电镜、X射线衍射、N2吸附脱附、热重分析和程序升温还原技术对催化剂及其前驱体进行了表征,考察了催化剂中Ni含量及焙烧和还原温度对催化剂催化对硝基苯酚加氢反应性能的影响.结果表明,Ni/TiO2催化剂不仅具有晶须状形貌和高结晶度的锐钛晶型,还保持了高比表面积和介孔结构.随着Ni/TiO2催化剂中镍负载量的增加,对硝基苯酚转化率逐渐增加,当镍负载量超过10%时,催化剂活性和选择性没有明显变化.当镍负载量为10%,焙烧和还原温度分别为500和450oC时,Ni/TiO2催化剂的加氢活性最佳,是RaneyNi的4倍.该催化剂循环使用7次后未发现明显失活.

A nano-sized nickel catalyst supported on mesoporous TiO2 whisker, Ni/TiO2, was prepared by incipient impregnation using Ni（NO3）2.6H2O solution. The physical and reduction characters of the Ni/TiO2 catalyst were measured by scanning electron microscopy, X-ray diffraction, N2 adsorption, thennogravimetric analysis, and temperature-programmed reduction, and its catalytic activity was investigated by p-nitrophenol hydrogenation. The results indicated that the catalyst possessed whisker morphology, high crystallinity anatase phase, high specific surface area, and mesostructure. It also showed high activity and stability. The conversion of p-nitrophenol over Ni/TiO2 increased with increasing nickel loading. When the nickel loading was over 10%, the catalyst activity and selectivity changed little. The 10%Ni/TiO2 catalyst calcined at 500 ℃ and reduced at 450 ℃ showed the best catalytic performance. The catalytic activity of Ni/TiO2 was four times higher than that of the commercial Raney nickel. No obvious deactivation of the catalyst was observed after repeated using seven times.