Zhang Shi-Nan, Gao Peng, Liu Qian-Yu, Zhang Zhao, Leng Bing-Liang, Chen Jie-Sheng, Li Xin-Hao
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
Nat Commun. 2024 Dec 30;15(1):10877. doi: 10.1038/s41467-024-55230-w.
Electrochemical nitrate reduction reaction offers a sustainable and efficient pathway for ammonia synthesis. Maintaining satisfactory Faradaic efficiency for long-term nitrate reduction under ampere-level current density remains challenging due to the inevitable hydrogen evolution, particularly in pure nitrate solutions. Herein, we present the application of electron deficiency of Ru metals to boost the repelling effect of counter K ions via the electric-field-dependent synergy of interfacial water and cations, and thus largely promote nitrate reduction reaction with a high yield and well-maintained Faradaic efficiency under ampere-level current density. The pronounced electron deficiency of Ru metals boosts the repelling effect on hydrated K ions, as indicated by the distance of K ions to catalyst surface, which can loosen the water layer to depress hydrogen evolution and accelerate nitrate conversion. Consequently, the optimized electrode loaded with electron-deficient Ru atomic layers can directly produce 0.26 M ammonia solution in pure nitrate solution in 6 h, providing a high yield (74.8 mg mg h) and well-maintained the Faradaic efficiency for over 120 h under ampere-level reduction.
电化学硝酸盐还原反应为氨合成提供了一条可持续且高效的途径。由于不可避免的析氢反应，在安培级电流密度下长期保持令人满意的法拉第效率用于硝酸盐还原仍然具有挑战性，特别是在纯硝酸盐溶液中。在此，我们展示了利用钌金属的电子缺陷，通过界面水和阳离子的电场依赖性协同作用来增强对反离子钾离子的排斥作用，从而在安培级电流密度下以高产率和良好维持的法拉第效率极大地促进硝酸盐还原反应。钌金属明显的电子缺陷增强了对水合钾离子的排斥作用，钾离子到催化剂表面的距离表明了这一点，这可以使水层松弛以抑制析氢并加速硝酸盐转化。因此，负载有缺电子钌原子层的优化电极能够在纯硝酸盐溶液中于6小时内直接产生0.26 M的氨溶液，在安培级还原条件下提供高产率（74.8 mg mg h）并在超过120小时内良好维持法拉第效率。
