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Single‐Crystalline Ultrathin Co3O4 Nanosheets with Massive Vacancy Defects for Enhanced Electrocatalysis
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2017-09-18 , DOI: 10.1002/aenm.201701694 Zhao Cai 1, 2 , Yongmin Bi 1 , Enyuan Hu 3 , Wen Liu 1, 2 , Nico Dwarica 2 , Yang Tian 1 , Xiaolin Li 2 , Yun Kuang 1 , Yaping Li 1 , Xiao-Qing Yang 3 , Hailiang Wang 2 , Xiaoming Sun 1, 4
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2017-09-18 , DOI: 10.1002/aenm.201701694 Zhao Cai 1, 2 , Yongmin Bi 1 , Enyuan Hu 3 , Wen Liu 1, 2 , Nico Dwarica 2 , Yang Tian 1 , Xiaolin Li 2 , Yun Kuang 1 , Yaping Li 1 , Xiao-Qing Yang 3 , Hailiang Wang 2 , Xiaoming Sun 1, 4
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The role of vacancy defects is demonstrated to be positive in various energy‐related processes. However, introducing vacancy defects into single‐crystalline nanostructures with given facets and studying their defect effect on electrocatalytic properties remains a great challenge. Here this study deliberately introduces oxygen defects into single‐crystalline ultrathin Co3O4 nanosheets with O‐terminated {111} facets by mild solvothermal reduction using ethylene glycol under alkaline condition. As‐prepared defect‐rich Co3O4 nanosheets show a low overpotential of 220 mV with a small Tafel slope of 49.1 mV dec−1 for the oxygen evolution reaction (OER), which is among the best Co‐based OER catalysts to date and even more active than the state‐of‐the‐art IrO2 catalyst. Such vacancy defects are formed by balancing with reducing environments under solvothermal conditions, but are surprisingly stable even after 1000 cycles of scanning under OER working conditions. Density functional theory plus U calculation attributes the enhanced performance to the oxygen vacancies and consequently exposed second‐layered Co metal sites, which leads to the lowered OER activation energy of 2.26 eV and improved electrical conductivity. This mild solvothermal reduction concept opens a new door for the understanding and future designing of advanced defect‐based electrocatalysts.
中文翻译：
具有大量空位缺陷的单晶超薄Co3O4纳米片增强了电催化作用
空缺缺陷的作用在各种与能源有关的过程中被证明是积极的。然而，将空位缺陷引入具有给定面的单晶纳米结构中并研究其缺陷对电催化性能的影响仍然是一个巨大的挑战。在此，本研究通过在碱性条件下使用乙二醇进行温和的溶剂热还原，故意将氧缺陷引入具有O端{111}面的单晶超薄Co 3 O 4纳米片中。制备的富含缺陷的Co 3 O 4纳米片表现出220 mV的低过电位，Tafel斜率小，为49.1 mV dec -1氧释放反应（OER）的反应，这是迄今为止最好的Co基OER催化剂之一，并且比最先进的IrO 2催化剂更具活性。这种空位缺陷是通过在溶剂热条件下与还原环境的平衡来形成的，但是即使在OER工作条件下进行1000个扫描周期后，这些空位缺陷仍然出奇地稳定。密度泛函理论和U计算将增强的性能归因于氧空位，因此暴露了第二层Co金属位点，这导致降低了2.26 eV的OER活化能并提高了电导率。这种温和的溶剂热还原概念为理解和进一步设计基于缺陷的高级电催化剂打开了一扇新门。
更新日期：2017-09-18
中文翻译：
具有大量空位缺陷的单晶超薄Co3O4纳米片增强了电催化作用
空缺缺陷的作用在各种与能源有关的过程中被证明是积极的。然而，将空位缺陷引入具有给定面的单晶纳米结构中并研究其缺陷对电催化性能的影响仍然是一个巨大的挑战。在此，本研究通过在碱性条件下使用乙二醇进行温和的溶剂热还原，故意将氧缺陷引入具有O端{111}面的单晶超薄Co 3 O 4纳米片中。制备的富含缺陷的Co 3 O 4纳米片表现出220 mV的低过电位，Tafel斜率小，为49.1 mV dec -1氧释放反应（OER）的反应，这是迄今为止最好的Co基OER催化剂之一，并且比最先进的IrO 2催化剂更具活性。这种空位缺陷是通过在溶剂热条件下与还原环境的平衡来形成的，但是即使在OER工作条件下进行1000个扫描周期后，这些空位缺陷仍然出奇地稳定。密度泛函理论和U计算将增强的性能归因于氧空位，因此暴露了第二层Co金属位点，这导致降低了2.26 eV的OER活化能并提高了电导率。这种温和的溶剂热还原概念为理解和进一步设计基于缺陷的高级电催化剂打开了一扇新门。
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