One major challenge of electrocatalytic dinitrogen (N₂) reduction is the competition between nitrogen reduction reaction (NRR) and hydrogen evolution reaction (HER). While experimental development of selective NRR catalysts is indispensable, the aim is to derive insights of catalyst design by developing a model that includes both the kinetics of competing reactions on the electrode and the mass transport of reactants in solution. The developed microkinetic model is reported here and it is applied to evaluate NRR selectivity on planar and microstructured electrodes. As a proof‐of‐principle, the model is numerically simulated under an aqueous electrolyte of 0.1 m nonoxidizing strong acid. The analysis indicates that while the first electron transfer to N₂ is rate‐limiting in most cases, under certain scenarios the impact of subsequent proton transfer on the reaction rate can be prominent. The microstructure of electrodes can pose a limit of N₂ mass transport and intriguingly cast a negative impact on the selectivity of N₂ fixation. Overall, the developed model interfaces the kinetics on electrode surfaces with the mass transport in the solution, and will serve as a general platform for the design and optimization of electrochemical N₂‐fixing process.

中文翻译：

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微结构化电极上电催化二氮还原的建模

电催化还原二氮（N ₂）的主要挑战是氮还原反应（NRR）和析氢反应（HER）之间的竞争。尽管选择性NRR催化剂的实验开发是必不可少的，但目的是通过开发一个模型来获得催化剂设计的见解，该模型既包括电极上竞争性反应的动力学，也包括溶液中反应物的质量迁移。本文报道了已开发的微动力学模型，并将其用于评估平面电极和微结构电极上的NRR选择性。作为原理的证明，该模型是在0.1 m非氧化性强酸的水性电解质下进行数值模拟的。分析表明，当第一个电子转移到N _2时在大多数情况下，它是限速的，在某些情况下，随后质子转移对反应速率的影响可能很明显。电极的微观结构可能会限制N _2的质量传输，并且对N ₂固定的选择性产生负面影响。总体而言，开发的模型将电极表面的动力学与溶液中的质量传递联系起来，并将作为电化学N ₂固定过程设计和优化的通用平台。