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Constructing Fe-N4 Sites through Anion Exchange-mediated Transformation of Fe Coordination Environments in Hierarchical Carbon Support for Efficient Oxygen Reduction |
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| Authors: | Dr Lingbo Zong Dr Kaicai Fan Lixiu Cui Fenghong Lu Prof Porun Liu Dr Bin Li Prof Shouhua Feng Prof Lei Wang |
| Institution: | 1. International Cooperation United Laboratory of Eco-chemical Engineering and Green Manufacturing, Technology Innovation Center of Battery Safety and Energy Storage Technology, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China;2. College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China
Contribution: Formal analysis (lead), Writing - review & editing (lead);3. International Cooperation United Laboratory of Eco-chemical Engineering and Green Manufacturing, Technology Innovation Center of Battery Safety and Energy Storage Technology, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China Contribution: Investigation (lead);4. International Cooperation United Laboratory of Eco-chemical Engineering and Green Manufacturing, Technology Innovation Center of Battery Safety and Energy Storage Technology, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China Contribution: Investigation (equal);5. Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Queensland, 4222 Australia Contribution: Resources (lead);6. College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China Contribution: Visualization (lead);7. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Chang-chun, 130012 China Contribution: Formal analysis (lead), Supervision (lead) |
| Abstract: | Metal single atoms (SAs) anchored in carbon support via coordinating with N atoms are efficient active sites to oxygen reduction reaction (ORR). However, rational design of single atom catalysts with highly exposed active sites is challenging and urgently desirable. Herein, an anion exchange strategy is presented to fabricate Fe-N4 moieties anchored in hierarchical carbon nanoplates composed of hollow carbon spheres (Fe-SA/N-HCS). With the coordinating O atoms are substituted by N atoms, Fe SAs with Fe-O4 configuration are transformed into the ones with Fe-N4 configuration during the thermal activation process. Insights into the evolution of central atoms demonstrate that the SAs with specific coordination environment can be obtained by modulating in situ anion exchange process. The strategy produces a large quantity of electrochemical accessible site and high utilization rate of Fe-N4. Fe-SA/N-HCS shows excellent ORR electrocatalytic performance with half-wave potential of 0.91 V (vs. RHE) in 0.1 M KOH, and outstanding performance when used in rechargeable aqueous and flexible Zn-air batteries. The evolution pathway for SAs demonstrated in this work offers a novel strategy to design SACs with various coordination environment and enhanced electrocatalytic activity. |
| Keywords: | Anion Exchange Reaction Coordination Environment Electrocatalysis Oxygen Reduction Reaction Single Atom |