Guan Yeqin, Liu Chuangwei, Wang Qianru, Gao Wenbo, Hansen Heine Anton, Guo Jianping, Vegge Tejs, Chen Ping
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2022 Sep 26;61(39):e202205805. doi: 10.1002/anie.202205805. Epub 2022 Aug 19.
Transition-metal-mediated dinitrogen fixation has been intensively investigated. The employment of main group elements for this vital reaction has recently sparked interest because of new dinitrogen reaction chemistry. We report ammonia synthesis via a chemical looping process mediated by a transition-metal-free barium hydride (BaH ). Experimental and computational studies reveal that the introduction of hydrogen vacancies is essential for creating multiple coordinatively unsaturated Ba sites for N activation. The adjacent lattice hydridic hydrogen (H ) then undergoes both reductive elimination and reductive protonation to convert N to NH . The ammonia production rate supports this hydride-vacancy mechanism via a chemical looping route that far exceeds that of a catalytic process. The BaH -mediated chemical looping process has prospects in future technologies for ammonia synthesis using transition-metal-free materials.
过渡金属介导的二氮固定已得到深入研究。由于新的二氮反应化学，使用主族元素进行这一重要反应最近引发了人们的兴趣。我们报道了通过无过渡金属的氢化钡（BaH₂）介导的化学循环过程合成氨。实验和计算研究表明，引入氢空位对于创造多个用于氮活化的配位不饱和钡位点至关重要。相邻的晶格氢负离子（H⁻）随后经历还原消除和还原质子化，将N₂转化为NH₃。氨的生成速率通过化学循环途径支持这种氢化物空位机制，该途径远远超过催化过程。BaH₂介导的化学循环过程在未来使用无过渡金属材料合成氨的技术中具有前景。
