Owing to their highly tailorable electrochemical characteristics and exceptional reactivity, high-entropy materials represent the next generation of water splitting catalysts. In this work, rare earth elements (Ho, Dy, Pr and Gd) were equivalently co-doped into the A-site of Y₂Ru₂O₇, successfully resulting in a new-type high-entropy pyrochlore (Y_0.2Ho_0.2Dy_0.2Gd_0.2Pr_0.2)₂Ru₂O₇ (HE-YRO). The electrocatalyst presents an extremely low overpotential (η = 200 mV) and unobvious inactivation during stability testing at 10 mA cm⁻². More remarkably, at η = 270 mV, it shows an excellent inherent mass activity of 797.1 A g_Ru⁻¹. By analyses of related pyrochlore oxides, several characteristics are confirmed for the HE-YRO electrocatalyst, which endow it with the high oxygen-evolution reaction (OER) performance. First of all, compared to those in YRO, more low-valent Ru³⁺ species and oxygen vacancies are induced in the HE-YRO structure, which improves the performance. Secondly, inhibition of the grain coarsening is caused by the lattice distortion, which would lead to large surface areas for HE-YRO and then increase the OER active sites. Thirdly, the Ru 4d band is extended, which results in an enhancement of conductivity and a strengthened hybridization between O 2p and Ru 4d orbitals, and then improves the reaction kinetics of the OER. Therefore, the synergistic effect of the above factors that are induced by the equivalent multielement doping at the A-site results in the superior OER performance and chemical durability of the HE-YRO electrocatalyst for acid-water oxidation. This work not only presents a novel method for creating advanced materials for obtaining renewable and clean energy but also validates the efficacy of high-entropy design.

中文翻译：

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一种新型烧绿石结构高熵酸水氧化电催化剂

由于其高度可定制的电化学特性和卓越的反应活性，高熵材料代表了下一代水分解催化剂。该工作将稀土元素（Ho、Dy、Pr和Gd）等价共掺杂到Y ₂ Ru ₂ O ₇的A位上，成功制备了新型高熵烧绿石（Y _0.2 Ho _0.2 Dy _0.2 Gd _0.2 Pr _0.2 ) ₂ Ru ₂ O ₇ (HE-YRO)。该电催化剂在10 mA cm ^-2稳定性测试中表现出极低的过电势（η = 200 mV）和不明显的失活。更值得注意的是，在η = 270 mV 时，它表现出 797.1 A g _Ru ^-1的优异固有质量活度。通过对相关烧绿石氧化物的分析，证实了HE-YRO电催化剂的几个特性，使其具有高析氧反应（OER）性能。首先，与YRO相比，HE-YRO结构中引入了更多的低价Ru ³⁺物种和氧空位，从而提高了性能。其次，晶格畸变抑制晶粒粗化，这会导致HE-YRO表面积增大，从而增加OER活性位点。第三，Ru 4d 能带扩展，导致电导率增强，O 2p 和 Ru 4d 轨道之间的杂化增强，从而改善 OER 的反应动力学。因此，A位等价多元素掺杂诱导的上述因素的协同效应导致HE-YRO酸水氧化电催化剂具有优异的OER性能和化学耐久性。这项工作不仅提出了一种创造先进材料以获得可再生和清洁能源的新方法，而且验证了高熵设计的有效性。