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

 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 2~3 nm. 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 10 MPa, 10 000 h?1 和 425 ºC 条件下, UEA 法制得的 Ru 基催化剂上氨合成反应速率达到 60.42 mmol/(g?h), 分别是 CI 法和 UC 法的 1.9 和 1.1 倍.

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

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 un...