Brea Courtney, Hu Guoxiang
Department of Chemistry and Biochemistry, Queens College, City University of New York, New York, New York 11367, United States.
The Graduate Center, City University of New York, New York, New York 10016, United States.
J Am Chem Soc. 2025 Jun 4;147(22):19210-19216. doi: 10.1021/jacs.5c04776. Epub 2025 May 23.
Metal-nitrogen-carbon (M-N-C, = Mn, Fe, Co, Ni, Cu, Zn, and Pt) dual-atom catalysts (DACs) show great potential for the oxygen reduction reaction (ORR) at the cathode of proton exchange membrane fuel cells (PEMFCs). During catalytic reactions, multiple reactants and intermediates interact with the active sites, yet understanding their dynamic structural evolution under the operating conditions remains challenging. In this study, we analyze 186 heteronuclear FeM-N-C DACs using thermodynamic phase diagrams and find that OH-ligated structures become predominant at higher applied potentials. This indicates that catalytic activity is governed by electrochemically modified metal sites rather than by the bare structures. We further investigate the catalytic mechanism of these ligated structures and reveal that the ORR limiting potential can be efficiently predicted from the phase diagrams. Among the 186 DACs studied, 29 were found to outperform Pt-based catalysts, with FeCo-N-C DACs demonstrating the highest activity. Our computational predictions align well with experimental observations, highlighting the crucial role of dynamic structural changes under reaction conditions in enhancing the electrocatalytic performance of DACs.
金属-氮-碳（M-N-C，M = Mn、Fe、Co、Ni、Cu、Zn和Pt）双原子催化剂（DAC）在质子交换膜燃料电池（PEMFC）阴极的氧还原反应（ORR）中显示出巨大潜力。在催化反应过程中，多种反应物和中间体与活性位点相互作用，但了解它们在操作条件下的动态结构演变仍然具有挑战性。在本研究中，我们使用热力学相图分析了186种异核FeM-N-C DAC，发现OH配位结构在较高的外加电位下占主导地位。这表明催化活性由电化学修饰的金属位点而非裸结构决定。我们进一步研究了这些配位结构的催化机制，并揭示可以从相图有效地预测ORR极限电位。在所研究的186种DAC中,发现有29种的性能优于基于Pt的催化剂，其中FeCo-N-C DAC表现出最高活性。我们的计算预测与实验观察结果吻合良好，突出了反应条件下动态结构变化在提高DAC电催化性能中的关键作用。
