Cobalt Phosphide Coupled with Heteroatom-Doped Nanocarbon Hybrid Electroctalysts for Efficient, Long-Life Rechargeable Zinc-Air Batteries
Cobalt Phosphide Coupled with Heteroatom-Doped Nanocarbon Hybrid Electroctalysts for Efficient, Long-Life Rechargeable Zinc-Air Batteries
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DOI：
10.1002/smll.201702068
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发表时间：
2017-10-25
期刊：
影响因子：
13.3
通讯作者：
Manthiram, Arumugam
中科院分区：
文献类型：
--
作者：
Ahn, Sung Hoon;Manthiram, Arumugam
金属磷化物和杂原子掺杂的碳被认为是有希望的双功能催化剂，用于析氧反应（OER）和氧还原反应（ORR）。然而，在锌-空气电池（ZAB）中的重复ORR和OER操作期间，两者都遭受稳定性问题。在此，本研究报告了一种通用的钴基杂化催化剂与一维结构的金属有机骨架衍生的转换方法和原位交联方法相结合。其中，由氮、硫、磷掺杂的碳基质负载的超小磷化钴纳米颗粒组成的一维杂化催化剂显示出与基准贵金属催化剂接近的显著双功能活性，沿着在覆盖OER和ORR的全电位范围内具有优异的耐久性。该双功能复合催化剂作为空气电极可大大降低ZABs的总过电位，且循环稳定性优于商业Pt/C催化剂。据透露，磷化钴纳米颗粒在加速条件下在ZAB的OER（和/或ORR）期间原位转化为钴氧化物，并降低施加到碳的阳极电流。这有助于碳材料的稳定性和保持混合催化剂的高初始催化性能。
Metal phosphides and heteroatom-doped carbons have been regarded as promising candidates as bifunctional catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). However, both have suffered from stability issues during repeated ORR and OER operations in zinc-air batteries (ZABs). Herein, this study reports a versatile cobalt-based hybrid catalyst with a 1D structure by integrating the metal-organic framework-derived conversion approach and an in situ crosslinking method. Among them, the 1D hybrid catalyst composed of ultrasmall cobalt phosphide nanoparticles supported by nitrogen-, sulfur-, phosphorus-doped carbon matrix shows remarkable bifunctional activity close to that of the benchmark precious-metal catalysts along with an excellent durability in the full potential range covering both the OER and ORR. The overall overpotential of the rechargeable ZABs can be greatly reduced with this bifunctional hybrid catalyst as an air-electrode, and the cycling stability outperforms the commercial Pt/C catalyst. It is revealed that the cobalt phosphide nanoparticles are in situ converted to cobalt oxide under the accelerated conditions during OER (and/or ORR) of the ZABs and reduces the anodic current applied to the carbon. This contributes to the stability of the carbon material and in maintaining the high initial catalytic properties of the hybrid catalyst.