Probing the active site in nonprecious metal-macrocyclic catalysts for ORR via multimodal operando X-ray and electrochemical spectroscopic studies
Hsiang-Ting Lien, Sun-Tang Chang, Po-Tuan Chen, Deniz P. Wong, Yu-Chung Chang, Ying-Rei Lu, Chung-Li Dong, Chen-Hao Wang, Kuei-Hsien Chen & Li-Chyong Chen
Nature Commmunictions 11, 4233 (2020).
Nonnoble metal catalysts are low-cost alternatives to Pt for the oxygen reduction reactions (ORRs), which have been studied for various applications in electrocatalytic systems. Among them, transition metal complexes, characterized by a redox-active single-metal-atom with biomimetic ligands, such as pyrolyzed cobalt–nitrogen–carbon (Co–N x /C), have attracted considerable attention. Therefore, we reported the ORR mechanism of pyrolyzed Vitamin B12 using operando X-ray absorption spectroscopy coupled with electrochemical impedance spectroscopy, which enables operando monitoring of the oxygen binding site on the metal center. material design strategies for high-performance electrocatalysts for fuel cell applications. Furthermore, the charge transfer mechanism between the catalyst and reactant enables further Co–O species formation. These experimental findings, provide insight into metal active-site geometry and structural evolution during ORR, which could be used for developing material design strategies for high performance electrocatalysts for fuel cell applications.