Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store
Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store
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DOI：
10.1038/nchem.1476
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发表时间：
2012-11-01
期刊：
影响因子：
21.8
通讯作者：
Hosono, Hideo
中科院分区：
文献类型：
--
作者：
Kitano, Masaaki;Inoue, Yasunori;Hosono, Hideo
工业上，人工将大气中的氮固定为氨是采用哈伯-博世工艺进行的，但该工艺需要高温高压，消耗的电力占世界发电量的1%以上。因此，人们正在寻找一种在更温和的条件下进行的对环境更加友好的过程。在这里，我们报道了一种负载Ru的电子化合物[Ca24Al28O64](4+)(e(-))(4) (Ru/C12A7:e(-))，具有高给电子能力和化学稳定性，可作为氨合成的有效催化剂。实现了高效的氨合成，其催化活性比之前报道的其他负载钌的催化剂高一个数量级，并且反应活化能几乎是一半。红外光谱动力学分析表明，C12A7:e(-)通过电子回馈显着增强了Ru上的N-2解离，并且由于C12A7:e(-)具有可逆储氢能力，可以有效抑制氢吸附原子对钌表面的毒化。
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.