Engineering the Electronic Structure of Single‐Atom Iron Sites with Boosted Oxygen Bifunctional Activity for Zinc–Air Batteries
Engineering the Electronic Structure of Single‐Atom Iron Sites with Boosted Oxygen Bifunctional Activity for Zinc–Air Batteries
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设计具有增强氧双功能活性的锌-空气电池单原子铁位点的电子结构
DOI：
10.1002/adma.202209644
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发表时间：
2022
影响因子：
29.4
通讯作者：
Junfa Zhu
中科院分区：
文献类型：
--
作者：
Zhijun Li;Siqi Ji;Chang Xu;Leipeng Leng;Hongxue Liu;J. Horton;Lei Du;Jincheng Gao;C. He;X. Qi;Qian Xu;Junfa Zhu
可充电锌 - 空气电池通常需要高效、耐用且价格低廉的双功能电催化剂来支持氧还原/析出反应（ORR/OER）。然而，如果要提高这些催化剂的性能，就必须解决动力学缓慢和传质困难的问题。在此，开发了一种制备催化剂的策略，该催化剂由原子级分散的铁原子负载在具有可及金属位点和优化的金属 - 载体电子相互作用的介孔氮掺杂碳载体（Fe SAs/NC）上构成。实验结果和理论计算均表明，金属活性位点的工程化电子结构可以调节铁中心的电荷分布，从而优化含氧中间体的吸附/解吸。含有Fe1N4O1位点的Fe SAs/NC在整个pH范围内都实现了显著的ORR活性，在碱性、酸性和中性电解质中，其半波电位分别为0.93 V、0.83 V和0.75 V（相对于可逆氢电极）。此外，它在碱性条件下对于OER在10 mA cm⁻²的电流密度下表现出320 mV的有前景的低过电位。用Fe SAs/NC组装的锌 - 空气电池在峰值功率密度、比容量和循环稳定性方面比Pt/C + RuO2组装的电池表现出更优异的性能。这些发现证明了金属位点的电子结构工程在指导催化活性方面的重要性。
Rechargeable zinc–air batteries typically require efficient, durable, and inexpensive bifunctional electrocatalysts to support oxygen reduction/evolution reactions (ORR/OER). However, sluggish kinetics and mass transportation challenges must be addressed if the performance of these catalysts is to be enhanced. Herein, a strategy to fabricate a catalyst comprising atomically dispersed iron atoms supported on a mesoporous nitrogen‐doped carbon support (Fe SAs/NC) with accessible metal sites and optimized electronic metal–support interactions is developed. Both the experimental results and theoretical calculations reveal that the engineered electronic structures of the metal active sites can regulate the charge distribution of Fe centers to optimize the adsorption/desorption of oxygenated intermediates. The Fe SAs/NC containing Fe1N4O1 sites achieves remarkable ORR activity over the entire pH range, with half‐wave potentials of 0.93, 0.83, and 0.75 V (vs reversible hydrogen electrode) in alkaline, acidic, and neutral electrolytes, respectively. In addition, it demonstrates a promising low overpotential of 320 mV at 10 mA cm−2 for OER in alkaline conditions. The zinc–air battery assembled with Fe SAs/NC exhibits superior performance than that of Pt/C+RuO2 counterpart in terms of peak power density, specific capacity, and cycling stability. These findings demonstrate the importance of the electronic structure engineering of metal sites in directing catalytic activity.