Duan Xinde, Ren Shuangshuang, Ge Fayuan, Zhu Xukun, Zhang Mingdao, Zheng Hegen
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, Jiangsu, PR China.
School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing 210044, Jiangsu, PR China.
Nanoscale. 2021 Oct 28;13(41):17655-17662. doi: 10.1039/d1nr04537g.
Metal-organic framework (MOF)-derived carbon composites with embedded metal alloy/metal oxides have attracted much attention due to their low-cost and excellent electrochemical reactivity. However, the drawback of this concept is the severe carbon evaporation during their synthesis, resulting in a reduction of active sites and catalytic durability. To solve this problem, this study proposes the possibility of using Ketjen black (KB) to replenish the carbon content. Impressively, MOF-derived bimetal and oxide N-doped porous carbon (CoNi-CoO-NiO@NC-800) exhibits extremely high catalytic activity with an oxygen reduction reaction (half-wave potential: 0.83 V) and oxygen evolution reaction (overpotential: 352 mV @ 10 mA cm) potential gap of 0.75 V due to the virtue of the hierarchically porous structure and sufficient active sites. By combining theoretical studies, a strong synergetic coupling of the CoNi dual metal is proposed in decreasing the overall reaction barriers and promoting the reversible oxygen reactions. Moreover, the assembled liquid- and all-solid-state Zn-air batteries (ZABs) with the bifunctional catalyst as the air cathode demonstrate superior discharging (223 mW cm at 310 mA cm) and charging-discharging performance and long lifetime (450 cycles, 75 h). This work will provide guidance for the rational design of metal/carbon hybrid catalysts and cut-price reproducible energy systems.
具有嵌入金属合金/金属氧化物的金属有机框架（MOF）衍生碳复合材料因其低成本和优异的电化学反应活性而备受关注。然而，这一概念的缺点是在其合成过程中会发生严重的碳蒸发，导致活性位点减少和催化耐久性降低。为了解决这个问题，本研究提出了使用科琴黑（KB）来补充碳含量的可能性。令人印象深刻的是，MOF衍生的双金属和氧化物氮掺杂多孔碳（CoNi-CoO-NiO@NC-800）由于其分层多孔结构和充足的活性位点，在氧还原反应（半波电位：0.83 V）和析氧反应（过电位：10 mA cm时为352 mV）中表现出极高的催化活性，电位差为0.75 V。通过结合理论研究，提出了CoNi双金属在降低整体反应势垒和促进可逆氧反应方面的强协同耦合作用。此外，以双功能催化剂作为空气阴极组装的液流和全固态锌空气电池（ZABs）表现出优异的放电（310 mA cm时为223 mW cm）和充放电性能以及长寿命（450次循环，75小时）。这项工作将为金属/碳混合催化剂的合理设计和廉价可再生能源系统提供指导。
