Full Bulk‐Structure Reconstruction into Amorphorized Cobalt–Iron Oxyhydroxide Nanosheet Electrocatalysts for Greatly Improved Electrocatalytic Activity,Small Methods

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Full Bulk‐Structure Reconstruction into Amorphorized Cobalt–Iron Oxyhydroxide Nanosheet Electrocatalysts for Greatly Improved Electrocatalytic Activity
Small Methods ( IF 10.7 ) Pub Date : 2020-09-01 , DOI: 10.1002/smtd.202000546
Xiaotong Han _{1,

2} , Chang Yu ₁ , Yingying Niu ₁ , Zhao Wang ₁ , Yingbo Kang ₂ , Yongwen Ren ₁ , Hui Wang ₁ , Ho Seok Park ₂ , Jieshan Qiu _{1,

3}

Affiliation

The electrochemical oxidation is considered as an innovative chemical strategy to induce the structure reconstruction for the enhanced electrocatalytic performances. However, the structure reconstruction is limited to the shallow surface, not achieving full utilization of inner active components. Herein, the full bulk‐structure reconstruction into highly active amorphorized cobalt–iron oxyhydroxide nanosheets through the electrochemical oxidation of the cobalt–iron phosphide precatalyst is reported. As confirmed by ex situ X‐ray diffraction and photoelectron, Raman, and electron energy‐loss spectroscopies, the phosphorus species leached from the phosphide provide etching effect, promoting the oxidation of residual cobalt‐iron species for in‐depth bulk amorphorization. The unique core‐shell structure of amorphorized cobalt–iron oxyhydroxide nanosheets encapsulated by the carbon shell (denoted as Co_0.8Fe_0.2OOH @ C) is constructed to offer highly exposed abundant active sites and fast charge transfer capability. The excellence of the full structure reconstructed Co_0.8Fe_0.2OOH@C electrocatalysts is confirmed demonstrating greatly improved activity (low overpotentials of 254 and 292 mV at 10 and 100 mA cm⁻²) and long‐term durability (negligible activity decay for continuous operation of 15 days at 100 mA cm⁻²) for oxygen evolution reaction applications.

中文翻译：

完整的体结构重建为非晶化的钴-羟基氧化铁纳米片电催化剂，可大大提高电催化活性

电化学氧化被认为是诱导结构重构以增强电催化性能的创新化学策略。但是，结构重建仅限于浅表面，不能充分利用内部活性成分。在此，据报道，通过钴-磷化铁预催化剂的电化学氧化，可以将完整的整体结构重建为高活性非晶化的钴-羟基氧化铁纳米片。通过异位X射线衍射，光电子，拉曼光谱和电子能谱分析证实，从磷化物中浸出的磷具有蚀刻作用，促进了残留的钴铁物种的氧化，从而促进了深入的本体非晶化。_0.8 Fe _0.2 OOH @ C）可提供高度暴露的丰富活性位点和快速电荷转移能力。证实了完整结构重建的Co _0.8 Fe _0.2 OOH @ C电催化剂的卓越表现，表明其活性大大提高（在10和100 mA cm ^-2时，低过电位为254和292 mV ）和长期耐用性（连续运行的活性衰减可忽略不计）在100 mA cm ^{-2的温度下}放置15天（氧气释放反应应用）。

更新日期：2020-10-07

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