College of Energy, Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, 215006, Suzhou, China.
University of Electronic Science and Technology of China, 610054, Chengdu Sichuan, China.
Nat Commun. 2019 Jan 21;10(1):341. doi: 10.1038/s41467-018-08120-x.
Ambient electrochemical N reduction is emerging as a highly promising alternative to the Haber-Bosch process but is typically hampered by a high reaction barrier and competing hydrogen evolution, leading to an extremely low Faradaic efficiency. Here, we demonstrate that under ambient conditions, a single-atom catalyst, iron on nitrogen-doped carbon, could positively shift the ammonia synthesis process to an onset potential of 0.193 V, enabling a dramatically enhanced Faradaic efficiency of 56.55%. The only doublet coupling representing NH in an isotopic labeling experiment confirms reliable NH production data. Molecular dynamics simulations suggest efficient N access to the single-atom iron with only a small energy barrier, which benefits preferential N adsorption instead of H adsorption via a strong exothermic process, as further confirmed by first-principle calculations. The released energy helps promote the following process and the reaction bottleneck, which is widely considered to be the first hydrogenation step, is successfully overcome.
环境电化学 N 还原作为哈伯-博世工艺的一种极具前景的替代方法正在兴起，但通常受到高反应势垒和竞争的析氢反应的阻碍，导致法拉第效率极低。在这里，我们证明在环境条件下，单原子催化剂——氮掺杂碳负载的铁，能够将氨合成过程正向移动到起始电位 0.193 V，从而显著提高法拉第效率至 56.55%。在同位素标记实验中，唯一的双峰耦合代表 NH，证实了可靠的 NH 生成数据。分子动力学模拟表明，氮能够高效地进入单原子铁，所需的能量势垒很小，这有利于优先吸附 N，而不是通过强放热过程吸附 H，这一点也被第一性原理计算进一步证实。释放的能量有助于促进后续的反应过程，并且被广泛认为是第一步加氢反应的反应瓶颈也被成功克服。
