Nitrogen is a fundamental constituent for all living creatures on the Earth and modern industrial society. The current nitrogen industry is largely powered by fossil fuels with huge energy consumption and carbon dioxide emission, and nitrogen pollution in surface water bodies induced by the indiscriminate discharge of industrial and domestic wastewater has become a worldwide environmental concern. Electrochemical techniques for nitrogen fixation and transformation under mild conditions are promising approaches to meet the challenge of efficiently managing and balancing the nitrogen cycle, where the rational design of advanced electrocatalysts from both structural and compositional aspects down to the nanoscale plays the most essential role. Herein, important nitrogen species including dinitrogen (N₂), ammonia (NH₃) and hydrazine (N₂H₄), their transformation processes between each other including the nitrogen reduction reaction (NRR), ammonia oxidation reaction (AOR) and hydrazine oxidation reaction (HzOR), and research progress on the development of related electrocatalysts are systematically summarized, aiming at establishing a general picture of the whole nitrogen cycle instead of a certain single reaction. Strategies combining theoretical computations and experimental optimizations are proposed to improve the catalytic performance including activity, efficiency, selectivity and stability, finally contributing to a self-sufficient and carbon-free “green” nitrogen economy.

中文翻译：

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电化学固氮和利用：理论，先进的催化剂材料和系统设计。

氮是地球和现代工业社会上所有生物的基本组成部分。当前的氮工业主要由消耗大量能源和二氧化碳的化石燃料驱动，由于工业和生活废水的不加选择的排放而引起的地表水体氮污染已成为全球环境关注的问题。在温和条件下用于固氮和转化的电化学技术是解决有效管理和平衡氮循环的挑战的有前途的方法，其中从结构和组成方面一直到纳米级的先进电催化剂的合理设计都起着至关重要的作用。在此，重要的氮物种包括二氮（N ₂），氨（NH ₃）和肼（N ₂ H ₄）之间的相互转化过程，包括氮还原反应（NRR），氨氧化反应（AOR）和肼氧化反应（HzOR），以及关于系统地总结了相关电催化剂的开发，旨在建立整个氮循环的概况，而不是某个单一的反应。提出了将理论计算和实验优化相结合的策略，以提高催化性能，包括活性，效率，选择性和稳定性，最终有助于实现自给自足且无碳的“绿色”氮经济。