Chinese Journal of Catalysis ›› 2013, Vol. 34 ›› Issue (2): 361-366.DOI: 10.3724/SP.J.1088.2012.20744

• Research papers • Previous Articles     Next Articles

Effect of Alkali Earth Metals on Performance of Zirconium-Based Perovskite Composite Oxides Supported Ruthenium for Ammonia Synthesis

WANG Ziqing, MA Yuncui, LIN Jianxin*, WANG Rong, WEI Kemei   

  1. National Engineering Research Center of Chemical Fertilizer Catalyst, Fuzhou University, Fuzhou 350002, Fujian, China
  • Received:2012-07-26 Revised:2012-09-06 Online:2013-02-05 Published:2013-02-05

Abstract: Zirconium-based perovskite materials with different alkaline earth metals were synthesized by the citric acid method and used as supports for ruthenium catalysts to catalytic ammonia synthesis reaction. The effects of alkaline earth metals on the texture properties, basicity, and catalytic activity were discussed. Additionally, the desorption properties of H2 on the surface of various catalysts were characterized by temperature-programmed desorption. The results showed that there were lots of strong basic sites appeared on the Ca, Sr, and Ba perovskite-style supports, and the order of activity was Ba > Sr > Ca. The addition of different alkaline earth metals not only affected the electron donating ability but also influenced the metal-support interaction as well as the adsorption-desorption properties of these catalysts. The adsorption of H2 was inhibited significantly by the presence of BaZrO3 and increased the number of active sites for dissociatively adsorbed N2 which may be the major reason why the Ru/BaZrO3 catalyst exhibited so high activity for ammonia synthesis.

Key words: alkaline earth metal, perovskite, zirconium, ruthenium catalysts, ammonia synthesis