In Situ Structural Evolution and Activity Descriptor of Atomically Dispersed Catalysts During Nitrate Electroreduction

作者：D. P. A. F. Braga, Angus Pedersen, Mohd Riyaz, Jesús Barrio, Alexander Bagger, Itamar T. Neckel, Thiago M. Mariano, Manuel E. G. Winkler, Ifan E. L. Stephens, Maria‐Magdalena Titirici, Raphael Nagao · 发表于：Advanced Science · 年份：2025 · DOI：10.1002/advs.202510282 · 被引用次数：11 · 研究领域：Ammonia Synthesis and Nitrogen Reduction、Advanced Photocatalysis Techniques、Nanomaterials for catalytic reactions

Abstract Single‐Atom Catalysts (SAC) have emerged as a promising class of materials for various catalytic applications, including the electrochemical nitrate reduction reaction (eNO 3 RR) and consequently ammonia production. While the efficiency and selectivity of these materials have been extensively highlighted for the eNO 3 RR, the in situ evolution to their structure and composition during electrocatalysis is largely unexplored and lacks catalyst design principles. To solve this, we investigated a series of high utilization metal‐nitrogen‐carbon (MNC) SACs (M = Cr, Fe, Co, Ni, and Cu) for eNO 3 RR. Except for CuNC, which selectively produced nitrite, all catalysts exhibited Faradaic efficiencies (FE) for ammonia exceeding 50%. NiNC demonstrated the highest performance (FE of 78.0 ± 2.9% at −0.4 V versus reversible hydrogen electrode (RHE) at pH 13 and maximum ammonia production rate of 615.7 ± 176.5 µmol·h −1 ·, corresponding to an energy efficiency of 15.1 ± 1.4% at −0.6 V RHE ), followed by CoNC. In situ Synchrotron X‐ray fluorescence (SXRF) mapping at various cathodic potentials (from open circuit potential to 0.0 V RHE and then −0.6 V RHE at 100 mV steps) revealed significant mobility of Ni within the carbon matrix, leading to the formation of metallic clusters from 0.0 V RHE . Similar in situ metal clustering is observed for CoNC. Structure‐activity plots are generated from both MNC literature and results obtained here, finding a clear trend between OH binding energy...