Iridium Single Atoms Coupling with Oxygen Vacancies Boosts Oxygen Evolution Reaction in Acid Media.
Iridium Single Atoms Coupling with Oxygen Vacancies Boosts Oxygen Evolution Reaction in Acid Media.
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DOI：
10.1021/jacs.0c05050
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发表时间：
2020-09
影响因子：
15
通讯作者：
Jie Yin;Jing Jin;Min Lu;Bolong Huang;Hong Zhang;Yong Peng;Pinxian Xi;Chunhua Yan
中科院分区：
文献类型：
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作者：
Jie Yin;Jing Jin;Min Lu;Bolong Huang;Hong Zhang;Yong Peng;Pinxian Xi;Chunhua Yan
同时实现提高的活性、增强的稳定性和降低的成本仍然是在酸中电催化析氧反应（OER）的研究中期望的但具有挑战性的目标。本文采用共电沉积法在NiCo 2 O 4多孔纳米片上制备了单原子铱（Ir-SAs）。表面暴露的Ir-SA与氧空位（VO）的偶联表现出增强催化剂在酸性介质中的OER活性和稳定性。它们显示出优异的上级OER性能，在j = 10 mA cm-2时具有240 mV的超低过电位，在酸性介质中的长期稳定性为70 h。在300和370 mV的过电位下的1.13和6.70 s-1的TOF也证实了其出色的性能。密度泛函理论（DFT）计算结果表明，在本征VO存在的NiCo 2 O 4表面，Ir原子的引入促进了表面电子交换和转移，从而提高了OER性能. Ir原子的存在大大提高了VO附近低配位Co原子的电子活性，促进了表面电子交换和转移能力。在这种趋势下，优选的H2O活化和稳定的 *O已经朝向竞争性较低的过电位达到。这是优化提高OER性能的通用关键。
Simultaneous realization of improved activity, enhanced stability, and reduced cost remains a desirable yet challenging goal in the search of electrocatalysis oxygen evolution reaction (OER) in acid. Herein, we report a novel strategy to prepare iridium single-atoms (Ir-SAs) on ultrathin NiCo2O4 porous nanosheets (Ir-NiCo2O4 NSs) by co-electrodeposition method. The surface exposed Ir-SAs couplings with oxygen vacancies (VO) exhibit boosting the catalysts OER activity and stability in acid media. They display superior OER performance with an ultralow overpotential of 240 mV at j = 10 mA cm-2 and long-term stability of 70 h in acid media. The TOFs of 1.13 and 6.70 s-1 at an overpotential of 300 and 370 mV also confirm their remarkable performance. Density functional theory (DFT) calculations reveal that the prominent OER performance arises from the surface electronic exchange-and-transfer activ-ities contributed by atomic Ir incorporation on the intrinsic VO existed NiCo2O4 surface. The atomic Ir sites substantially elevate the electronic activity of surface lower coordinated Co-sites nearby VO, which facilitate the surface electronic exchange-and-transfer capabilities. With this trend, the preferred H2O-activation and stabilized *O have been reached towards competitively lower overpo-tential. This is a generalized key for optimally boosting OER performance.