Yang Huimin, Wang Hao, Cheng Haorong, Xu Xinyuan, Li Jing, He Xiaoyan, Tian Lin, Li Zhao
University and College Key Lab of Natural Product Chemistry and Application in Xinjiang, School of Chemistry and Environmental Science, Yili Normal University, Yining, 835000, China.
School of Materials and Chemical Engineering, Xuzhou University of Technology, Xuzhou, 221018, China.
Chemistry. 2024 Dec 10;30(69):e202402972. doi: 10.1002/chem.202402972. Epub 2024 Oct 26.
Developing efficient bifunctional oxygen electrocatalysts is crucial for enhancing the performance of rechargeable Zn-air batteries (ZABs). In this study, cobalt/cobalt oxides embedded in N-doped carbon nanofibers (Co/CoO/NCNFs) were synthesized through a combination of electrospinning and annealing processes. The resulting Co/CoO/NCNFs catalysts feature abundant CoN and CoO active species, leveraging the large specific surface area of nanofibers to facilitate oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The optimized Co/CoO/NCNFs-0.1 achieved a half-wave potential (vs. RHE) of 0.82 V and required only 429 mV to reach 10 mA cm in a typical three-electrode system with 0.1 M KOH using an electrochemical workstation equipped with a pine instruments rotator, outperforming the Pt/C+RuO. The assembled ZABs exhibited high specific capacity (771 mAh g ), substantial power density (981.6 mWh g ), and long-term stability (>325 h). In situ Raman spectroscopy confirmed that the electrocatalytic processes involve the redox activity of Co (II and III) species derived from abundant CoN and CoO, elaborating the origin of the catalysts' exceptional oxygen electrocatalysis performance. This work not only presents a straightforward and effective approach for producing bifunctional oxygen electrocatalysts in ZABs but also sheds light on the catalytic mechanisms underlying ORR and OER for CoN/CoO-based oxygen electrocatalysts.
开发高效的双功能氧电催化剂对于提高可充电锌空气电池（ZABs）的性能至关重要。在本研究中，通过静电纺丝和退火工艺相结合的方法合成了嵌入氮掺杂碳纳米纤维（Co/CoO/NCNFs）中的钴/氧化钴。所得的Co/CoO/NCNFs催化剂具有丰富的CoN和CoO活性物种，利用纳米纤维的大比表面积促进氧还原反应（ORR）和析氧反应（OER）。优化后的Co/CoO/NCNFs-0.1在配备松仪器旋转器的电化学工作站中，于0.1 M KOH的典型三电极系统中实现了0.82 V的半波电位（相对于RHE），达到10 mA cm只需429 mV，性能优于Pt/C+RuO。组装的ZABs表现出高比容量（771 mAh g）、高功率密度（981.6 mWh g）和长期稳定性（>325 h）。原位拉曼光谱证实，电催化过程涉及源自丰富CoN和CoO的Co（II和III）物种的氧化还原活性，阐明了催化剂卓越的氧电催化性能的起源。这项工作不仅提出了一种在ZABs中制备双功能氧电催化剂的直接有效方法，还揭示了基于CoN/CoO的氧电催化剂的ORR和OER的催化机制。
