Metal-Organic-Framework-Derived Hybrid Carbon Nanocages as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution
Metal-Organic-Framework-Derived Hybrid Carbon Nanocages as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution
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DOI：
10.1002/adma.201700874
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发表时间：
2017-08-18
影响因子：
29.4
通讯作者：
Qiu, Jieshan
中科院分区：
文献类型：
--
作者：
Liu, Shaohong;Wang, Zhiyu;Qiu, Jieshan
氧还原反应（ORR）和析氧反应（OER）是许多可再生能源技术的基础反应。开发廉价而耐用的贵金属催化剂替代品，特别是对ORR和OER反应具有高活性的双功能电催化剂及其简化的耦合过程，对于降低可再生能源系统的处理成本和复杂性是非常期望的。在这里，报道了一种简便的策略，用于通过对核-壳金属-有机框架的模板合成具有Co-N-掺杂的石墨碳（Co-NGC）的外壳和N-掺杂的微孔碳（NC）的内壳的双壳混合纳米笼。双壳NC@Co-NGC纳米笼很好地将Co-NGC壳的高活性整合到具有增强的扩散动力学的坚固的NC中空骨架中，作为ORR和OER的双功能电催化剂，表现出比Pt和RuO 2更上级的电催化性能，并且有望作为锌-空气电池中的高效空气电极催化剂。第一性原理计算表明，Co-NGC壳层的高催化活性是由于Co纳米颗粒、石墨碳和掺杂N物种之间的协同电子转移和再分配。相对于Co-NGC结构中的Co晶格，OOH* 中间体在高密度的未配位的空心碳原子上的强而有利的吸附是实现优异的双功能电催化活性的重要速率决定步骤。
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are cornerstone reactions for many renewable energy technologies. Developing cheap yet durable substitutes of precious-metal catalysts, especially the bifunctional electrocatalysts with high activity for both ORR and OER reactions and their streamlined coupling process, are highly desirable to reduce the processing cost and complexity of renewable energy systems. Here, a facile strategy is reported for synthesizing double-shelled hybrid nanocages with outer shells of Co-N-doped graphitic carbon (Co-NGC) and inner shells of N-doped microporous carbon (NC) by templating against core-shell metal-organic frameworks. The double-shelled NC@Co-NGC nanocages well integrate the high activity of Co-NGC shells into the robust NC hollow framework with enhanced diffusion kinetics, exhibiting superior electrocatalytic properties to Pt and RuO2 as a bifunctional electrocatalyst for ORR and OER, and hold a promise as efficient air electrode catalysts in Zn-air batteries. First-principles calculations reveal that the high catalytic activities of Co-NGC shells are due to the synergistic electron transfer and redistribution between the Co nanoparticles, the graphitic carbon, and the doped N species. Strong yet favorable adsorption of an OOH* intermediate on the high density of uncoordinated hollowsite C atoms with respect to the Co lattice in the Co-NGC structure is a vital rate-determining step to achieve excellent bifunctional electrocatalytic activity.