A series of Ba-Ru/MgO catalysts were prepared by the impregnation method using commerical (mark as MgO-1) and synthesized MgO (mark as MgO-2) as the support, respectively. The catalysts were characterized by XRD, TG/DSC, N2 adsorption-desorption, TEM, H2 TPR and C02 TPD. The effect of MgO support and BaO promoter were investigated on the phase structure, texture structure and morphology, reduction process of ruthenium particles, surface properties and catalytic activity in ammonia synthesis. The results indicate that the physical and chemical properties of MgO support have a strong impact on the structure and activity of ruthenium catalyst. The specific surface area and total basic sites number of MgO-2 was higher than that of MgO-1, Ru particles supported over the surface of MgO-2 was about 2 nm and easy to be reduced. When the molar ratio of b.:ru was 1.0, weak basic sites appeared over the surface of Ba-Ru(l :l)/MgO-2, which greatly promoted the ammonia synthesis rate. The ammonia synthesis activity was 15.40 L^g'^'h"1 at 3.0 Mpa>5 000 h"1 and 400 t for Ba-Ru(l:l)/MgO-2, which was higher than that of Ba-Ru/MgO-1 catalysts at the same conditions.%采用不同来源氧化镁(市售MgO-1,合成MgO-2)作为钌基氨合成催化剂载体,浸渍法制备了添加不同BaO助剂含量的Ba-Ru/MgO催化剂,通过X射线衍射(XRD)、热重-量热扫描分析(TG/DSC)、N2-低温物理吸附、透射电镜(TEM)、H2程序升温还原(H2-TPR)和CO2程序升温脱附(CO2-TPD)等手段对其进行了表征,考察了不同来源的MgO和BaO助剂含量对负载型钌基氨合成催化剂的物相结构、织构性质、微观形貌、Ru物种的还原性质和体系酸碱性质以及催化剂的氨合成活性等方面的影响.结果表明,MgO的理化性质对所制备的钌基氨合成催化剂的结构以及氨合成活性有较大影响.MgO-2比表面较大,总碱性位数量较多,负载在其表面的Ru粒子粒径在2nm左右,nBa:nRu为1.0时,Ba-Ru( 1:1 )/MgO-2催化剂表面的Ru物种易于还原,表面存在的弱碱性位极大地促进了氨合成活性,在400°C时活性达到15.40 L·g-1.·h-1(3.0 MPa,5 000 h-1),在相同反应条件下比Ba-Ru/MgO-1催化剂活性更高.
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