Laboratory of Industrial Chemistry, Ruhr-University Bochum, 44780, Bochum, Germany.
Analytical Chemistry-Center for Electrochemical Sciences (CES), Ruhr-University Bochum, 44780, Bochum, Germany.
Angew Chem Int Ed Engl. 2016 Mar 14;55(12):4087-91. doi: 10.1002/anie.201509382. Epub 2016 Feb 23.
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 H2 atmosphere and subsequent controlled oxidative calcination. The catalysts afford 0.85 V reversible overvoltage in 0.1 m KOH, surpassing Pt/C, IrO2 , and RuO2 and thus ranking them among one of the best non-precious-metal electrocatalysts for reversible oxygen electrodes.
高效的可逆氧电极对于各种能量转换设备（如再生燃料电池和金属-空气电池）的氧气还原反应（ORR）和氧气析出反应（OER）至关重要。然而，由于水分解和氧气还原用的电催化剂的活性和稳定性不足，实现这种电极受到阻碍。我们报告了由嵌入在 CNT 接枝的 N 掺杂碳多面体中的核壳 Co@Co3O4 纳米粒子组成的高度活性的氧电极双功能电催化剂，该多面体是通过在还原 H2 气氛中热解钴金属有机骨架（ZIF-67）并随后进行受控氧化煅烧而获得的。该催化剂在 0.1m KOH 中提供 0.85V 的可逆过电压，超过了 Pt/C、IrO2 和 RuO2，从而将其列为用于可逆氧电极的最佳非贵金属电催化剂之一。
