美国得克萨斯大学奥斯汀分校Guihua Yu团队报道了亚硝酸盐中间体串联催化的脉冲硝酸-氨电还原。相关研究成果于2023年3月10日发表于国际顶尖学术期刊《美国化学会杂志》。

硝酸盐电还原制氨提供了一种具有能源和环境可持续性的废水养分循环和回收途径。在调节反应路径以促进硝酸盐制氨的转化方面已经做出了大量研究，但仅取得了有限的成功。

该文中，研究人员报道了一种铜单原子凝胶（Cu-SAG）电催化剂，它在中性条件下从硝酸盐和亚硝酸盐中产生NH₃。鉴于具有空间限制和强化动力学的Cu-SAGs上NO₂^-活化的独特机制，提出了脉冲电解策略，以级联NO₃^-还原过程中NO₂^-中间体的积累和转化，并阻止来自析氢反应的竞争，因此与恒电位电解相比，显著提高了用于氨生产的法拉第效率和产率。

该项工作强调了脉冲电解和具有三维（3D）框架结构的SAGs的合作方法，以通过不利中间体的串联催化实现高效硝酸盐制氨。

附：英文原文

Title: Pulsed Nitrate-to-Ammonia Electroreduction Facilitated by Tandem Catalysis of Nitrite Intermediates

Author: Panpan Li, Ran Li, Yuanting Liu, Minghao Xie, Zhaoyu Jin, Guihua Yu

Issue&Volume: March 10, 2023

Abstract: Electroreduction of nitrate to ammonia offers a promising pathway for nutrient recycling and recovery from wastewater with energy and environmental sustainability. There have been considerable efforts on the regulation of reaction pathways to facilitate nitrate-to-ammonia conversion over the competing hydrogen evolution reaction but only with limited success. Here, we report a Cu single-atom gel (Cu SAG) electrocatalyst that produces NH3 from both nitrate and nitrite under neutral conditions. Given the unique mechanism of NO2– activation on Cu SAGs with spatial confinement and strengthened kinetics, a pulse electrolysis strategy is presented to cascade the accumulation and conversion of NO2– intermediates during NO3– reduction with the prohibited competition from the hydrogen evolution reaction, thus substantially enhancing the Faradaic efficiency and the yield rate for ammonia production compared with constant potential electrolysis. This work underlines the cooperative approach of the pulse electrolysis and SAGs with three-dimensional (3D) framework structures for highly efficient nitrate-to-ammonia conversion enabled by tandem catalysis of unfavorable intermediates.

DOI: 10.1021/jacs.3c00334

Source: https://pubs.acs.org/doi/10.1021/jacs.3c00334