Effect of rare earth on the performance of Ru/MgAl-LDO catalysts for ammonia synthesis
来源期刊：JOURNAL OF RARE EARTHS2018年第2期
论文作者：Jun Ni Baoqiang Jing Jianxin Lin Bingyu Lin Ziqi Zhao Lilong Jiang
文章页码：135 - 141
摘 要：A series of MgAl-layered double oxides（LDO） doped with different rare-earth elements（Y, La, and Ce）were synthesized by the calcination of Mg-Al layered double hydroxides, and Ru, which were used to prepare ammonia synthesis catalysts. The as-obtained oxides and catalysts were characterized by XRD,TEM, TPD, TPR and XPS to understand their catalytic performances in ammonia synthesis. The H2-TPR and HRTEM studies reveal that Ru/Y-LDO catalyst possesses more active Ru metal and small particle size.The XPS demonstrates that the electronic interaction between Y and Ru metals is stronger, which can be tentatively explained by most of Y inserted into the hydrotalcites structure. CO2-TPD demonstrates that Ru/Y-LDO catalyst shows stronger basic site densities than catalysts doped with Ce and La. Higher activity of the Ru/Y-LDO catalyst can be attributed to smaller particle size, more active metal（Ru） and strong Ru-support interaction.
Jun Ni，Baoqiang Jing，Jianxin Lin，Bingyu Lin，Ziqi Zhao，Lilong Jiang
National Engineering Research Center of Chemical Fertilizer Catalyst,School of Chemical Engineering, Fuzhou University
摘 要：A series of MgAl-layered double oxides（LDO） doped with different rare-earth elements（Y, La, and Ce）were synthesized by the calcination of Mg-Al layered double hydroxides, and Ru, which were used to prepare ammonia synthesis catalysts. The as-obtained oxides and catalysts were characterized by XRD,TEM, TPD, TPR and XPS to understand their catalytic performances in ammonia synthesis. The H2-TPR and HRTEM studies reveal that Ru/Y-LDO catalyst possesses more active Ru metal and small particle size.The XPS demonstrates that the electronic interaction between Y and Ru metals is stronger, which can be tentatively explained by most of Y inserted into the hydrotalcites structure. CO2-TPD demonstrates that Ru/Y-LDO catalyst shows stronger basic site densities than catalysts doped with Ce and La. Higher activity of the Ru/Y-LDO catalyst can be attributed to smaller particle size, more active metal（Ru） and strong Ru-support interaction.
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