Aqueous electrolytes are extensively applied in electrochemical nitrogen reduction reaction, while the overwhelming HO always produce much protons, favoring the electron-stealing hydrogen evolution reaction (HER) and thus leaving the current ammonia synthesis much to be desired. Here, we propose an aqueous-aprotic hybrid electrolyte system by introducing trimethyl phosphate (TMP) as a cosolvent to achieve highly selective ammonia synthesis. TMP features higher Gutmann donors than that of HO, preferring to serve as hydrogen bond (HB) acceptor and reshaping the HB network in the electrolyte. Molecular dynamics simulations suggest that, compared with HO-HO HB, the HO-TMP HB exhibits longer lifetime and better stability. The intensified interaction between HO and TMP weakens the interaction between HO and HO, which strengthens the O-H bond of HO and makes it more difficult to be broken, thus greatly inhibiting the dissociation of HO and leading to a suppressed HER activity. Correspondingly, a significantly improved NRR performance with a superior NH yield rate of 82.1 ± 2.7 μg h mg and an optimum Faradaic efficiency of 73.3 ± 2.7% is achieved in the HO-TMP hybrid electrolyte, indicative of order of magnitude enhancement compared with that delivered in the conventional aqueous electrolyte.

中文翻译：

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重塑水-非质子混合电解质中的氢键网络以实现高选择性常温氨合成

水电解质广泛应用于电化学氮还原反应，而大量的H2O总是产生大量质子，有利于电子窃取析氢反应（HER），从而使目前的氨合成方法还很不理想。在这里，我们提出了一种水-非质子混合电解质系统，通过引入磷酸三甲酯（TMP）作为共溶剂来实现高选择性氨合成。 TMP 具有比 H2O 更高的古特曼供体，更愿意充当氢键 (HB) 受体并重塑电解质中的 HB 网络。分子动力学模拟表明，与HO-HO HB相比，HO-TMP HB具有更长的寿命和更好的稳定性。 H2O与TMP相互作用的增强，削弱了H2O与H2O之间的相互作用，使H2O的OH键增强，使其更难断裂，从而极大地抑制了H2O的解离，导致HER活性受到抑制。相应地，HO-TMP 混合电解质显着提高了 NRR 性能，NH 产率高达 82.1 ± 2.7 μg h mg，最佳法拉第效率为 73.3 ± 2.7%，这表明与交付的电解质相比，性能提高了数量级。在传统的水性电解质中。