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Engineering the Coordination Environment of Single Cobalt Atoms for Efficient Oxygen Reduction and Hydrogen Evolution Reactions
ACS Catalysis ( IF 11.3 ) Pub Date : 2021-03-29 , DOI: 10.1021/acscatal.0c05577
Tao Sun 1, 2 , Wenjie Zang 3 , Huan Yan 4 , Jing Li 2 , Zhiqi Zhang 5 , Yongfeng Bu 6 , Wei Chen 2 , John Wang 3 , Jiong Lu 2 , Chenliang Su 1
Affiliation  

The coordination environment of single-atom catalysts (SACs) plays a crucial role in determining the energy conversion efficiency of related electrochemical devices. Herein, the coordination environment of a series of Co-based SACs (Co1-SACs) was tuned to correlate the chemical structures of these catalysts with their electrocatalytic performance. The optimized Co1-SACs containing Co-S2N2 sites are electrocatalytically active in both the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), which were carried out in alkaline media. The Co1-SACs containing Co-S2N2 sites exhibit high ORR activity, with an onset potential of 0.99 V vs RHE and good stability, as well as have promising application in a zinc-oxygen battery with a high power density (260 mW cm–2) and open-circuit voltage (1.50 V), remarkable tolerance to large current density, and long-term operation. The ORR of the Co-S2N2 site is attributed to the optimized electron density of the Co atom through its cocoordination with adjacent S and N atoms. Moreover, the Co1-SACs efficiently catalyze the HER, exhibiting a low overpotential (121 mV at 20 mA cm–2), a low Tafel slope (47 mV dec–1), and long-term stability. This work also provides a facile heteroatom-doping strategy to engineer the desired coordination environments in SACs for efficient electrocatalysis.

中文翻译:

设计单个钴原子的配位环境以实现高效的氧还原和氢生成反应

单原子催化剂(SAC)的配位环境在确定相关电化学装置的能量转换效率方面起着至关重要的作用。在本文中,调整了一系列基于Co的SAC(Co 1 -SAC)的配位环境,以将这些催化剂的化学结构与其电催化性能相关联。含有Co-S 2 N 2位的优化的Co 1 -SAC具有在碱性介质中进行的氧还原反应(ORR)和析氢反应(HER)的电催化活性。含Co-S 2 N 2的Co 1 -SAC这些位点显示出高ORR活性,相对RHE的起始电势为0.99 V,并且具有良好的稳定性,并且在具有高功率密度(260 mW cm –2)和开路电压(1.50)的锌氧电池中具有广阔的应用前景V),对大电流密度的显着耐受性以及长期运行。Co-S 2 N 2位点的ORR归因于Co原子与相邻的S和N原子的配位,从而优化了Co原子的电子密度。而且,Co 1 -SAC有效地催化了HER,表现出较低的过电势(20 mA cm –2时为121 mV ),较低的Tafel斜率(dec m -1为47 mV)。),长期稳定。这项工作还提供了一种简便的杂原子掺杂策略,可在SAC中设计所需的配位环境以进行有效的电催化。
更新日期:2021-04-16
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