无溶剂高度分散Ni/MCM-41催化剂的制备及其萘加氢性能

分别用机械研磨无溶剂法、添加柠檬酸无溶剂法制备了Ni/MCM-41催化剂,对所制催化剂进行了分析表征,探究其萘加氢反应性能并与常规浸渍法进行了对比。与常规浸渍法相比,机械研磨无溶剂法所制催化剂的物理性质相近,金属镍分散度和萘加氢性能略有提高;添加柠檬酸无溶剂法则显著提升了催化剂的分散度和萘加氢性能,金属镍分散度由6.9%大幅提高至67.9%,萘加氢性能提高了近1倍。通过红外光谱、紫外光谱和热重分析,提出了添加柠檬酸对无溶剂法制备催化剂性能的促进作用机制。

Highly Dispersed Ni/MCM-41 Catalyst: Solvent-Free Preparation and Performance for Hydrogenation of Naphthalene

Ni/MCM-41 catalysts were prepared with a solvent-free method of mechanical grinding. Furtherly, Ni/MCM-41(CA) catalyst was also prepared by adding citric acid during preparation of Ni/MCM-41. Compared with Ni/MCM-41(IM) catalyst prepared with the conventional impregnation method, the physical properties of the catalyst with the solvent-free method were almost unchanged. And the dispersion of metallic nickel and the performance of naphthalene hydrogenation were slightly improved. After adding citric acid during preparation of Ni/MCM-41, the dispersion of metallic nickel in Ni/MCM-41(CA) catalyst was greatly increased from 6.9% to 67.9%, and the performance of naphthalene hydrogenation was nearly enhanced 100%. Through infrared spectroscopy, UV spectra and thermogravimetric analysis, the promotion mechanism for adding citric acid in the solvent-free method was attributed to forming a kind of nickel citrate by adding citric acid during preparation of Ni/MCM-41.