Identification of the Electronic and Structural Dynamics of Catalytic Centers in Single-Fe-Atom Material

By Xuning Li, Changyu Cao, Sung-Fu Hung, Ying-Rui Lu, Weizheng Cai, A. Rykov, S. Miao, S. Xi, Hongbin Yang, Zehua Hu and 12 more. Chem, 2020

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Summary The lack of model single-atom catalysts (SACs) and atomic-resolution operando spectroscopic techniques greatly limits our comprehension of the nature of catalysis. Herein, based on the designed model single-Fe-atom catalysts with well-controlled microenvironments, we have explored the exact structure of catalytic centers and provided insights into a spin-crossover-involved mechanism for oxygen reduction reaction (ORR) using operando Raman, X-ray absorption spectroscopies, and the developed operando 57Fe Mossbauer spectroscopy. In combination with theoretical studies, the N-FeN4C10 moiety is evidenced as a more active site for ORR. Moreover, the potential-relevant dynamic cycles of both geometric structure and electronic configuration of reactive single-Fe-atom moieties are evidenced via capturing the peroxido (∗O2−) and hydroxyl (∗OH−) intermediates under in situ ORR conditions. We anticipate that the integration of operando techniques and SACs in this work shall shed some light on the electronic-level insight into the catalytic centers and underlying reaction mechanism.

View Paper: https://www.semanticscholar.org/paper/239b7456ee25f4e59d1b0be7fd18ddc14394bbc8