溶胶—凝胶法制备NiO／SiO2催化剂研究

分别以正硅酸乙酯、硝酸镍为硅源和镍源，采用溶胶－凝胶法，经超临界流体干燥和普通干燥制备了NiO-A-SiO2、NiO-G-SiO2催化剂；以气凝胶和干凝胶为载体，采用浸渍法制备了NiO/A-SiO2、NiO/G-SiO2催化剂。并用XRD、TEM、BET、TPR等手段，研究了制备方法对催化剂织构、结构和Ni物种存在形态的影响，发现NiO-A-SiO2和NiO-G-SiO2催化剂上高度分散的NiO簇团与SiO2之间有较强的相互作用，其顺酐液相选择加氢转化率低于10％；NiO/G-SiO2催化剂上，以单一物种形态存在的NiO与SiO2相互作用弱，顺酐转化率为42％；NiO/A-SiO2催化剂上，以多种形态存在的微量NiO与SiO2间的相互作用较复杂，其顺酐液相选择加氢的转化率和丁二酸酐的选择性分别可达100％和98％。

Study on the NiO/SiO2 Catalysts Prepared by Sol-Gel Method

Using Ni(NO\-3)\-2 and TEOS as nickel and silica sources, NiO\|SiO\-2 catalysts were prepared by Sol\|Gel\|SCFD and general dry methods(designated by NiO\|A\|SiO\-2 and NiO\|G\|SiO\-2, respectively), NiO\|SiO\-2 catalysts were also prepared by impregnation of SiO\-2 aerogel and xerogel, both of which was prepared by Sol\|Gel(designated by NiO/A\|SiO\-2 and NiO/G\|SiO\-2, respectively). The effects of preparation methods on the texture, structure and the existing forms of NiO species of Ni\|based catalysts were investigated using TEM, BET, XRD and TPR. The results show that NiO\|A\|SiO\-2 and NiO\|G\|SiO\-2 catalysts have the same texture and structure with a strong interaction between NiO and SiO\-2, since small NiO clusters are uniformly distributed inside the support material. These catalysts have a conversion of MA less than 10% in catalytic hydrogenation. The NiO/G\|SiO\-2 catalyst has a very weak interaction between NiO and SiO\-2 due to the existence of NiO in single form, which has a 42% conversion of MA. The NiO/A\|SiO\-2 catalyst has different forms of NiO species and an moderate interaction with SiO\-2, it shows the highest performance in catalytic hydrogenation, conversion of MA 100% and selectivity to SA more than 98%.