Co@Co3O4 Encapsulated in Carbon Nanotube-Grafted Nitrogen-Doped Carbon Polyhedra as an Advanced Bifunctional Oxygen Electrode
Co@Co3O4 Encapsulated in Carbon Nanotube-Grafted Nitrogen-Doped Carbon Polyhedra as an Advanced Bifunctional Oxygen Electrode
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DOI：
10.1002/anie.201509382
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发表时间：
2016-03-14
影响因子：
16.6
通讯作者：
Muhler, Martin
中科院分区：
文献类型：
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作者：
Aijaz, Arshad;Masa, Justus;Muhler, Martin
用于氧还原反应（ORR）和析氧反应（OER）的高效可逆氧电极对于再生燃料电池和金属-空气电池等各种能量转换装置至关重要。然而，这种电极的实现受到电催化剂在水分解和氧还原方面的活性和不稳定性不足的阻碍。我们报道了一种高活性的双功能电催化剂，用于氧电极，该电催化剂由核壳Co@Co3O4纳米颗粒嵌入碳纳米管接枝的n掺杂碳多角体中，这些碳多角体是通过在还原性H-2气氛中热解钴金属有机框架（ZIF-67）和随后的受控氧化煅烧得到的。在0.1m KOH条件下，该催化剂的可逆过电压为0.85V，超过Pt/C、IrO2和RuO2，是最佳的可逆氧电极非贵金属电催化剂之一。
Efficient reversible oxygen electrodes for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are vitally important for various energy conversion devices, such as regenerative fuel cells and metal-air batteries. However, realization of such electrodes is impeded by insufficient activity and instability of electrocatalysts for both water splitting and oxygen reduction. We report highly active bifunctional electrocatalysts for oxygen electrodes comprising core-shell Co@Co3O4 nanoparticles embedded in CNT-grafted N-doped carbon-polyhedra obtained by the pyrolysis of cobalt metal-organic framework (ZIF-67) in a reductive H-2 atmosphere and subsequent controlled oxidative calcination. The catalysts afford 0.85V reversible overvoltage in 0.1m KOH, surpassing Pt/C, IrO2, and RuO2 and thus ranking them among one of the best non-precious-metal electrocatalysts for reversible oxygen electrodes.