Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store

作者：Kitano, Masaaki^*; Inoue, Yasunori; Yamazaki, Youhei; Hayashi, Fumitaka; Kanbara, Shinji; Matsuishi, Satoru; Yokoyama, Toshiharu; Kim, Sung-Wng; Hara, Michikazu; Hosono, Hideo

来源：Nature Chemistry, 2012, 4(11): 934-940.

DOI：10.1038/NCHEM.1476

• SUPPORTED RUTHENIUM CATALYSTS
• PROMOTED TRANSITION-METAL
• ADSORBED DINITROGEN
• SINGLE-CRYSTAL
• WORK FUNCTION
• ALKALI-METAL
• BARIUM
• ACTIVATION
• SURFACES
• KINETICS

Industrially, the artificial fixation of atmospheric nitrogen to ammonia is carried out using the Haber-Bosch process, but this process requires high temperatures and pressures, and consumes more than 1% of the world's power production. Therefore the search is on for a more environmentally benign process that occurs under milder conditions. Here, we report that a Ru-loaded electride [Ca24Al28O64](4+)(e(-))(4) (Ru/C12A7:e(-)), which has high electron-donating power and chemical stability, works as an efficient catalyst for ammonia synthesis. Highly efficient ammonia synthesis is achieved with a catalytic activity that is an order of magnitude greater than those of other previously reported Ru-loaded catalysts and with almost half the reaction activation energy. Kinetic analysis with infrared spectroscopy reveals that C12A7:e(-) markedly enhances N-2 dissociation on Ru by the back donation of electrons and that the poisoning of ruthenium surfaces by hydrogen adatoms can be suppressed effectively because of the ability of C12A7:e(-) to store hydrogen reversibly.

• 出版日期2012-11