水热沉积法制备高分散W/Al_2O_3加氢脱硫催化剂  

Highly Dispersed W/Al_2O_3 Hydrodesulfurization Catalyst Prepared by Hydrothermal Deposition Method

作　　者：王豪[1] 范煜[1] 石冈[1] 刘海燕[1] 鲍晓军[1] 

机构地区：[1]中国石油大学(北京)中国石油天然气集团公司催化重点实验室

出　　处：《催化学报》2007年第4期364-370,共7页

基　　金：国家重点基础研究发展计划(973计划;2004CB217807).

摘　　要：提出了一种用于制备高分散型W／Al2O3加氢脱硫催化剂的水热沉积法．该方法利用钨酸钠和盐酸在水热条件下的沉积反应生成纳米WO3，通过加入表面活性剂十六烷基三甲基溴化铵可防止WO3颗粒的团聚，从而实现了WO3在Al2O3载体上的高分散负载．采用X射线光电子能谱、高分辨率透射电镜、N2物理吸附以及氢气程序升温还原等技术对W／Al2O3催化剂进行了表征，并以二苯并噻吩的加氢脱硫作为模型反应评价了催化剂的催化性能．结果表明，与采用常规浸渍法制备的具有相同活性组分含量的催化剂相比，采用水热沉积法制备的催化剂具有更高的WTO3分散度（表面W／Al原子比从0．051提高到0．061）、更大的比表面积和孔体积；活性组分与载体间的相互作用减弱，WO3的最高还原温度从1030℃降低到1015℃，预硫化后催化剂上的活性物种WS2具有更短的片层长度和更高的堆积程度，WS2片层的平均长度从7．78nm减小到5．71nm，平均堆积层数从1．23增加到1．41；催化剂对二苯并噻吩的加氢脱硫活性比浸渍法制备的催化剂高15％～18％．A novel hydrothermal deposition method for preparing the highly dispersed W/Al2O3 hydrodesulfurization catalyst was developed and compared with the conventional impregnation method. By the hydrothermal deposition method, WO3 was deposited on the γ-Al2O3 support via the precipitation reaction of sodium tungstate and hydrochloric acid under hydrothermal conditions. A cation surfactant hexadecyltrimethylammonium bromide （CTABr） was used in the hydrothermal deposition process to prevent the aggregation of WO3 particles. The catalyst was characterized by X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, N2 adsorption, and temperature-programmed reduction. The catalyst activity was tested using hydrodesulfurization of dibenzothiophene. The results showed that compared with the catalyst prepared by the impregnation method, the catalyst with the same metal content prepared by the hydrothermal deposition method had higher dispersion of tungsten species, larger specific surface area and pore volume, weaker metal-support interaction, and shorter length and higher stacking of WS2 slabs. As a result, the activity of the catalyst prepared by hydrothermal deposition was 15% -18% higher than that of the catalyst prepared by the impregnation method. The high dispersion of tungsten species and the weak interaction between tungsten species and alumina in the catalyst prepared by hydrothermal deposition should be attributed to the low diffusion resistance of the hydrothermal solution and the structural stabilization effect of the surfactant CTABr.

关 键 词：水热沉积 钨 氧化铝 二苯并噻吩 加氢脱硫 高分散 弱相互作用 

分 类 号：O643.3[理学—物理化学]