The sluggish reaction kinetics of oxygen evolution reaction (OER) and the high price of noble metal catalysts hinder the wide application of water electrolysis for hydrogen generation. High-entropy oxides (HEOs) with multi-components and high entropy stabilized structures have attracted great research interests due to their efficient and durable performance in electrolytic water splitting reactions. However, the development of efficient HEO electrocatalysts are often hindered by the limited surface exposed active sites because high temperature is usually required to form a high entropy stabilized structure. Herein, a flaky high-entropy oxide with a spinel structure, (FeCoNiCrMn)O, was synthesized by using the sacrificial layered carbon template in situ prepared by the volatile reaction between ammonium sulfate and molten glucose. High-resolution TEM results show the as-prepared (FeCoNiCrMn)O flakes are composed of nanosized HEO particles. The nanosized (FeCoNiCrMn)O HEO electrocatalysts exhibit excellent OER activity, with an overpotential of 239 mV at 10 mA/cm and a Tafel slope of 52.4 mV/dec. The electrocatalyst has excellent stability. Even at a high current density of 100 mA/cm, the activity remains unchanged during the stability test for 24 h. The results here shed a new light in the design and fabrication of highly efficient HEO electrocatalysts.

中文翻译：

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轻松合成纳米尖晶石高熵氧化物 (FeCoNiCrMn)3O4 以实现高效的析氧反应

析氧反应（OER）缓慢的反应动力学和贵金属催化剂的高价格阻碍了水电解制氢的广泛应用。具有多组分和高熵稳定结构的高熵氧化物（HEO）由于其在电解水分解反应中高效且持久的性能而引起了人们的广泛研究兴趣。然而，高效HEO电催化剂的开发常常受到有限的表面暴露活性位点的阻碍，因为通常需要高温来形成高熵稳定的结构。本文利用硫酸铵与熔融葡萄糖挥发反应制备的牺牲层状碳模板原位合成了具有尖晶石结构的片状高熵氧化物(FeCoNiCrMn)O。高分辨率 TEM 结果表明所制备的 (FeCoNiCrMn)O 薄片由纳米级 HEO 颗粒组成。纳米级 (FeCoNiCrMn)O HEO 电催化剂表现出优异的 OER 活性，在 10 mA/cm 下的过电势为 239 mV，塔菲尔斜率为 52.4 mV/dec。该电催化剂具有优异的稳定性。即使在100 mA/cm的高电流密度下，24小时的稳定性测试中活性也保持不变。这里的结果为高效 HEO 电催化剂的设计和制造提供了新的思路。