Identifying the Key Role of Pyridinic‐N–Co Bonding in Synergistic Electrocatalysis for Reversible ORR/OER |
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| Authors: | Xue‐Rui Wang Jie‐Yu Liu Zi‐Wei Liu Wei‐Chao Wang Jun Luo Xiao‐Peng Han Xi‐Wen Du Shi‐Zhang Qiao Jing Yang |
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| Affiliation: | 1. Institute of New‐Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, China;2. College of Electronic Information and Optical Engineering, Nankai University, Tianjin, China;3. Center for Electron Microscopy, TUT‐FEI Joint Laboratory, Tianjin Key Laboratory of Advanced Functional Porous Materials, Institute for New Energy Materials & Low‐Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, China;4. Institute of Advanced Metallic Materials, School of Materials Science and Engineering Tianjin University, Tianjin, China;5. School of Chemical Engineering, The University of Adelaide, Adelaide, SA, Australia |
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| Abstract: | For many regenerative electrochemical energy‐conversion systems, hybrid electrocatalysts comprising transition metal (TM) oxides and heteroatom‐doped (e.g., nitrogen‐doped) carbonaceous materials are promising bifunctional oxygen reduction reaction/oxygen evolution reaction electrocatalysts, whose enhanced electrocatalytic activities are attributed to the synergistic effect originated from the TM–N–C active sites. However, it is still ambiguous which configuration of nitrogen dopants, either pyridinic or pyrrolic N, when bonded to the TM in oxides, predominately contributes to the synergistic effect. Herein, an innovative strategy based on laser irradiation is described to controllably tune the relative concentrations of pyridinic and pyrrolic nitrogen dopants in the hybrid catalyst, i.e., NiCo2O4 NPs/N‐doped mesoporous graphene. Comparative studies reveal the dominant role of pyridinic‐N? Co bonding, instead of pyrrolic‐N bonding, in synergistically promoting reversible oxygen electrocatalysis. Moreover, density functional theory calculations provide deep insights into the corresponding synergistic mechanism. The optimized hybrid, NiCo/NLG‐270, manifests outstanding reversible oxygen electrocatalytic activities, leading to an overpotential different ΔE among the lowest value for highly efficient bifunctional catalysts. In a practical reversible Zn–air battery, NiCo/NLG‐270 exhibits superior charge/discharge performance and long‐term durability compared to the noble metal electrocatalysts. |
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| Keywords: | graphenes hybrid electrocatalysts pyridinic nitrogen pyrrolic nitrogen spinels |
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