制备方法对掺钡纳米氧化镁负载钌催化剂氨合成性能的影响  

Effect of Preparation Methods on Catalytic Properties of Ba-Doped Nano-MgO-Supported Ru Catalyst for Ammonia Synthesis

作　　者：霍超[1] 张学辉[1] 夏庆华[1] 杨霞珍[1] 骆燕[1] 刘化章[1] 

机构地区：[1]浙江工业大学化学工程与材料学院,浙江杭州310032

出　　处：《催化学报》2010年第3期360-364,共5页

基　　金：国家自然科学基金(20203016);浙江省自然科学基金(Y406294)

摘　　要：采用普通浸渍法（CI）、超声-包覆法（UC）和超声-静电吸附法（UEA）制备了Ru/Ba-MgO氨合成催化剂,并运用高分辨透射电镜、场发射扫描电镜、X射线粉末衍射、N2的物理吸附、H2脉冲化学吸附及程序升温还原等手段对催化剂进行了表征.结果表明,在UEA样品中,Ba以静电吸附形式均匀地掺入MgO载体中,因而不仅极大地改善了载体表面形貌,而且有效地控制了Ru晶粒大小,其平均粒径在2~3nm.该样品中,BaCO3起始分解温度较低,低温BaCO3含量较高,因而还原性能较佳.在10MPa,10000h？1和425oC条件下,UEA法制得的Ru基催化剂上氨合成反应速率达到60.42mmol/（g·h）,分别是CI法和UC法的1.9和1.1倍.Three Ru-based catalysts for ammonia synthesis were prepared by the conventional impregnation method （CI）, ultrasound-coating method （UC）, and ultrasound electrostatic adsorption （UEA）. The physical and chemical properties of the supports and catalysts were characterized by high-resolution transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, N2 physical adsorption, H2 pulse chemical adsorption, and temperature-programmed reduction （TPR）. The results showed that Ba was uniformly dispersed on the surface of the MgO support through its electrostatic adsorption in the catalyst prepared by UEA, which not only greatly improved the surface morphology of the support but also effectively controlled the size of Ru particles within the range 2–3 nm. TPR results also showed that the Ru-based catalyst prepared by UEA contained more BaCO3 species that decomposed at low temperature and therefore gave a better reduction property. The highest catalytic activity forammonia synthesis was obtained on the Ru-based catalyst prepared by UEA with a reaction rate of 60.42 mmol/（g·h） for ammonia synthesis under the conditions of 10 MPa, 10 000 h–1, and 425 oC, which is 1.9 and 1.1 times that of Ru-based catalysts prepared by CI and UC , respectively.

关 键 词：钡 纳米氧化镁 超声-包覆法 超声-静电吸附法 钌基催化剂 氨合成 

分 类 号：O643.36[理学—物理化学]