Electrochemical nitrate reduction (NO₃^–R) presents a promising pathway for carbon-neutral ammonia (NH₃) synthesis. Enhancing NH₃ selectivity through a tandem process can be achieved by combining Cu with a secondary metal, which allows for an adjustable binding energy between the bimetallic catalyst and key nitrogen intermediates. Herein, we developed a biphasic Ag–Cu heterostructure with a controllable elemental composition, which significantly improved NH₃ production through tandem NO₃^–R. In-situ infrared spectroscopy and finite element simulations revealed that Ag serves as the active site for converting NO₃^– to NO₂^–, leading to a high localized concentration of NO₂^–, which is subsequently reduced to NH₃ on adjacent Cu sites. Density functional theory calculations further confirmed the critical role of the Ag–Cu biphasic interface in promoting tandem NH₃ production. This work offers valuable insights into the tandem NO₃^–R pathway in bimetallic heterostructures, providing a foundation for optimizing catalysts and advancing large-scale sustainable NH₃ synthesis.

中文翻译：

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促进在 Ag-Cu 双相界面处从硝酸盐电化学合成氨


电化学硝酸盐还原 （NO₃^–R） 为碳中和氨 （NH₃） 合成提供了一种有前途的途径。通过将 Cu 与仲金属结合，可以通过串联工艺提高 NH₃ 选择性，这允许双金属催化剂和关键氮中间体之间的结合能可调。在此，我们开发了一种具有可控元素组成的双相 Ag-Cu 异质结构，通过串联 NO ^3-R 显着改善了 NH₃ 的产生。原位红外光谱和有限元模拟表明，Ag 是将 NO₃^– 转化为 NO₂^– 的活性位点，导致 NO₂^– 的高局部浓度，随后被还原为 NH₃在相邻的 Cu 位点上。密度泛函理论计算进一步证实了 Ag-Cu 双相界面在促进串联 NH₃ 产生中的关键作用。这项工作为双金属异质结构中的串联 NO ^3-R 途径提供了有价值的见解，为优化催化剂和推进大规模可持续 NH₃ 合成提供了基础。