两步氧化原位制备铁钴镍合金基水分解催化电极的研究

In-situ preparation of iron-cobalt-nickel alloy based water splitting catalytic electrode by two-step oxidation

采用包括恒电位氟化氧化以及碱性H_(2)O_(2)介质水热氧化在内的两步氧化法对FeCoNi三元合金进行原位处理,制备得到合金基氧化电极,重点讨论水热温度对电极催化性能的影响,分析相应的催化机理。结果表明:氟化氧化结合120℃条件下的碱性水热氧化制备得到的电极综合性能最佳,达到10 mA·cm^(-2)的OER及HER反应电流密度需要的过电位分别为187 mV和231 mV,该电极在50 h的稳定性测试中表现出优异的OER及HER稳定性。机理分析表明氟化氧化处理后的电极表面具有高反应活性,通过进一步水热氧化后发生表面重构,氟元素逸出并形成均匀分布具有高比表面积的纳米片状金属氢氧化物催化活性物种,从而赋予了电极优异的电化学催化活性。

A two-step oxidation method including potentiostatic fluorination-oxidation and hydrothermal oxidation in alkaline H_(2)O_(2)medium was used to treat FeCoNi ternary alloy to prepare catalytic electrode for water decomposition.The influence of hydrothermal temperature on the catalytic performance of the electrode was mainly discussed,and the corresponding catalytic mechanism was analyzed.The results showed that the electrode prepared by fluorination oxidation combined with alkaline hydrothermal oxidation at 120℃had the best performance,which could reach an OER and HER reaction current density of 10 mA·cm^(-2)with required overpotentials of 187 mV and 231 mV,respectively.The electrode exhibited excellent OER and HER stability in a 50-hour stability test.Mechanism analysis showed that the electrode surface after fluorination oxidation treatment had high reactivity.Through further hydrothermal oxidation,surface reconstruction occured to remove fluorine elements and form uniformly distributed nanosheet catalytic active species of metallic oxide(hydroxide)with high specific surface area,thereby endowing the electrode with excellent electrochemical catalytic activity.