Insights into the efficiency and stability of Cu-based nanowires for electrocatalytic oxygen evolution
Insights into the efficiency and stability of Cu-based nanowires for electrocatalytic oxygen evolution
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DOI：
10.1007/s12274-018-2020-1
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发表时间：
2018-08-01
期刊：
影响因子：
9.9
通讯作者：
Delaunay, Jean-Jacques
中科院分区：
文献类型：
--
作者：
Yu, Jun;Cao, Qi;Delaunay, Jean-Jacques
制备了不同氧化态的氧化铜纳米线，并对其水氧化活性进行了研究。具有CuO相的纳米线被发现是最活跃的，它们的结晶度对于实现高效的水氧化是重要的。在弱碱性Na2CO3电解液中，结晶CuO纳米线的Tafel斜率为41 mV/decade，在10 mA/cm(2)时的过电位约为500 mV（不补偿溶液电阻），法拉第效率接近100%。该电极在-10 mA/cm(2)下的过电位为500 mV， Tafel斜率小，长期稳定，成本低，使CuO成为最有前途的水氧化催化剂之一。此外，通过电子显微镜研究了CuO纳米线形貌随时间的演变，揭示了Cu离子从纳米线内部扩散到纳米线表面导致单个纳米线随时间的聚集。然而，尽管有这种聚集，电流密度几乎保持不变，因为CuO的总电化学活性表面积没有改变。
Copper oxide nanowires with varying oxidation states are prepared and their activity for water oxidation is studied. The nanowires with a CuO phase are found to be the most active, and their degree of crystallinity is important in achieving efficient water oxidation. For the crystalline CuO nanowires in a weakly basic Na2CO3 electrolyte, a Tafel slope of 41 mV/decade, an overpotential of approximately 500 mV at 10 mA/cm(2) (without compensation for the solution resistance), and a faradaic efficiency of nearly 100% are obtained. This electrode maintains a stable current for over 15 h. The low overpotential of 500 mV at -10 mA/cm(2), small Tafel slope, long-term stability, and low cost make CuO one of the most promising catalysts for water oxidation. Moreover, the evolution of the CuO nanowire morphology over time is studied by electron microscopy, revealing that the diffusion of Cu ions from the interior of the nanowires to their surface causes the aggregation of individual nanowires over time. However, despite this aggregation, the current density remains nearly constant, because the total electrochemically active surface area of CuO does not change.