超声波-微波法制备NiW/Al_2O_3加氢脱硫催化剂

Preparation of NiW/Al_2O_3 Hydrodesulfurization Catalyst by Ultrasound-Microwave Treatment

采用一次浸渍技术制备了NiW /Al2 O3 加氢脱硫 (HDS)催化剂 ,在制备过程中采用超声波处理浸渍液 ,采用微波进行样品干燥 .以噻吩为模型化合物 ,在微反装置上评价了该催化剂的加氢脱硫活性 .使用X射线光电子能谱和透射电镜等表征手段研究了催化剂的表面状态和物化性质 .结果表明 ,使用超声波及微波技术制备的NiW /Al2 O3 催化剂具有较高的加氢脱硫活性 ,催化剂的活性组分较易硫化 ,可生成更多的硫化物种参与反应 .催化剂中硫化态钨的表面原子浓度较高 ,从而使硫化态钨物种保持较高的表面分散度 ,有利于增加活性中心的数目 .该催化剂的活性中心结构具有较多配位不饱和的边缘位和棱边位 ,因而具有较高的加氢脱硫活性 .

Hydrotreating is one of the important means for the production of clean fuels and its efficiency largely depends on the hydrotreating catalysts. The preparation methods greatly influence the nature of the catalysts and result in different activity, selectivity and stability. In the present study, the NiW/Al 2O 3 catalyst was prepared by impregnation combined with ultrasound treatment and microwave drying. The catalytic properties, surface state and morphology of the catalyst were examined by using thiophene hydrodesulfurization, XPS and TEM techniques, respectively. The as-prepared catalyst exhibited higher hydrodesulfurization activity than that obtained by the conventional method. The XPS and TEM analysis revealed that combination of the ultrasound treatment and microwave drying could promote the sulfuration and surface dispersion of the active metals and produce more unsaturated 'rim' and 'edge' sites in the WS 2 slabs. As a result, the hydrodesulfurization activity of the as-prepared catalyst was remarkably enhanced.