The Key Steps and Distinct Performance Trends of Pyrrolic vs Pyridinic M–N–C Catalysts in Electrocatalytic Nitrate Reduction

作者：Qiuling Jiang, Mingyao Gu, Pei Shen, Tianyi Wang, Fangzhou Liu, Xin Yang, Di Zhang, Zhijian Wu, Ying Wang, Wei Li, Hao Li · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.5c09199 · 被引用次数：56 · 研究领域：Ammonia Synthesis and Nitrogen Reduction、Electrocatalysts for Energy Conversion、Hydrogen Storage and Materials

High Resolution Image Download MS PowerPoint Slide The electrochemical nitrate reduction reaction (NO 3 RR) offers a sustainable route for ambient ammonia synthesis. While metal–nitrogen–carbon (M–N–C) single-atom catalysts have emerged as promising candidates for the NO 3 RR, the structure–activity relations underlying their catalytic behavior remain to be elucidated. Through systematic analysis of reported experimental data and pH-field coupled microkinetic modeling on a reversible hydrogen electrode (RHE) scale, we reveal that the coordination-dependent activity originates from distinct scaling relations governed by metal-intermediate interactions. M-N-Pyrrolic catalysts generally demonstrate higher turnover frequencies for ammonia production than M-N-Pyridinic catalysts. Meanwhile, the adsorption and protonation of nitrate, which is a step often dismissed and/or assumed to be simultaneous in many previous reports, are identified to be the rate-determining step (RDS) in the NO 3 RR. Remarkably, our subsequent experimental validation confirms the theoretical predictions under both neutral and alkaline conditions. This study offers a comprehensive mechanistic framework for interpreting the electrocatalytic activity of M–N–C catalysts in the NO 3 RR, showing that a classical thermodynamic “limiting-potential model” is not sufficiently accurate to capture the RDS and the catalytic performance trends of different materials (even on M-N-Pyrrolic and M-N-Pyridinic catalysts). The...