Atomically thin high-entropy oxides via naked metal ion self-assembly for proton exchange membrane electrolysis

Here, we develop a self-assembly technique to synthesize 1-nm-thick rutile-structured high-entropy oxides (RuIrFeCoCrO₂) from naked metal ions assembly and oxidation at air-molten salt interface. The RuIrFeCoCrO₂ only requires an overpotential of 185 mV at 10 m A cm⁻² and maintains the high activity for over 1000 hours in an acidic electrolyte via the adsorption evolution mechanism. In this dataset, we calculated the desolvation coefficient (D) of various cations in aqueous solution and molten salt. In molten salt, the corresponding D for metal ions is higher by several orders of magnitude compared to that in water, which allows metal ions to become freely moving ions. We also conducted DFT calculations to gain insight to the structural stability and reaction mechanism of this HEO. The results show that the reaction mechanism changes from LOM (RuO₂) to AEM (RuIrFeCoCrO₂).

本研究开发了一种自组装技术，可通过裸金属离子组装与空气-熔盐界面氧化过程，合成厚度为1纳米的金红石结构的高熵氧化物（high-entropy oxides，RuIrFeCoCrO₂）。该RuIrFeCoCrO₂在10毫安每平方厘米的电流密度下仅需185毫伏的过电位，且在酸性电解质中通过吸附演化机制可维持高催化活性超过1000小时。本数据集中，我们计算了多种阳离子在水溶液与熔盐中的去溶剂化系数（desolvation coefficient，D）；在熔盐体系中，金属离子对应的去溶剂化系数相较于水溶液中高出数个数量级，这使得金属离子可成为自由移动的离子。本研究还通过密度泛函理论（DFT）计算，深入探究了该高熵氧化物（HEO）的结构稳定性与反应机制。结果表明，其反应机制从对应RuO₂的晶格氧机制（LOM）转变为对应RuIrFeCoCrO₂的吸附演化机制（AEM）。