Effect of constituent cations on the electrocatalytic oxygen evolution reaction in high-entropy oxide (Mg0.2Fe0.2Co0.2Ni0.2Cu0.2)O

Kim, Kyung-Hwan; Choi, Yun-Hyuk

doi:10.1016/j.jelechem.2022.116737

Cited by 15 publications

(5 citation statements)

References 47 publications

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“…Kim et al 78 used a unique method in a ground-breaking attempt to manufacture HEOs. They started by adding distilled water to a mixture of five different metal nitrates to dissolve them.…”

Section: Structural Characterizationmentioning

confidence: 99%

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Research Progress of High-Entropy Oxides as Oxygen Evolution Reaction Catalysts

Zhang,

You,

Zhang

et al. 2024

Energy Fuels

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Equimolar or nearly molar mixtures of five or more metals are used to create highentropy oxides (HEOs). HEOs also possess the kinetic slow diffusion effect, structural lattice distortion, the thermodynamic high-entropy effect, and the cocktail effect. Consequently, a growing number of scientists are investigating high-entropy oxides. High active site density, low overpotential, and entropic stabilization effects are the main reasons why HEOs now show good electrocatalytic oxygen evolution reaction. However, the complexity of the elemental composition, organization, and surface morphology of high-entropy oxides limits the use of HEOs. The development of HEOs and the mechanisms behind OER are reviewed in this work, along with a description of the OER response pathways and evaluation standards. The OER performance of HEOs with diverse organizational structures is reviewed in this research because HEOs come in a variety of kinds. Additionally, when HEOs are utilized as carriers, the trend of OER performance is examined. Lastly, potential future development problems and opportunities for HEO electrocatalysts are discussed.

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“…Kim et al 78 used a unique method in a ground-breaking attempt to manufacture HEOs. They started by adding distilled water to a mixture of five different metal nitrates to dissolve them.…”

Section: Structural Characterizationmentioning

confidence: 99%

“…Kim et al 78 also used XPS to examine the surface properties in light of the critical function that surface morphology plays in electrocatalysis. Five elements were present in their respective oxidation states according to their data.…”

Section: Structural Characterizationmentioning

confidence: 99%

Research Progress of High-Entropy Oxides as Oxygen Evolution Reaction Catalysts

Zhang,

You,

Zhang

et al. 2024

Energy Fuels

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“…28 For instance, Kim electrocatalysts could contribute to an improved catalytic activity. 93 Moreover, the entropy stabilization is pivotal in electrochemical reactions, and reversibility is a necessary factor for entropy-driven transitions; Gu et al found that a single rock-salt structure appears only when the temperature reaches 1150 °C. In addition, Li has been proven to play a prominent role in enhancing the concentration of oxygen vacancies and optimizing the electrical conductivity, in which the electronic structure and electrical properties of defect engineering result in an enhanced OER kinetics.…”

Section: Spinel Heomentioning

confidence: 99%

“…The energetics of the OER intermediate can be regulated by adding other elements to the crystal lattice to achieve an optimized catalytic activity . For instance, Kim and co-workers synthesized (Mg 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 )O for the OER and confirmed that Cu 2+ can prevent the conversion from Fe 2+ and Co 2+ to Fe 3+ and Co 3+ , respectively, while increasing the concentration of Co 3+ in electrocatalysts could contribute to an improved catalytic activity . Moreover, the entropy stabilization is pivotal in electrochemical reactions, and reversibility is a necessary factor for entropy-driven transitions; Gu et al found that a single rock-salt structure appears only when the temperature reaches 1150 °C.…”

Section: High-entropy Oxides-based Electrocatalystsmentioning

confidence: 99%

High-Entropy Oxides as Electrocatalysts for the Oxygen Evolution Reaction: A Mini Review

Huang,

Wang,

et al. 2024

Energy Fuels

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It is crucial to develop cost-effective and high-efficiency catalysts for electrochemical water splitting. High-entropy oxides (HEOs) are promising emerging catalysts for the oxygen evolution reaction (OER) with outstanding catalytic activity and remarkable durability because of their flexibility and structural stability, as well as the synergistic effect of various elements. Herein, a panoramic view of the mechanism of the OER of HEO and the evaluation criteria for the performance of the OER of HEO are discussed. A sequence of key discoveries and achievements of HEO-based OER electrocatalysts with different structures such as perovskite, spinel, and rock-salt structures has been summarized, together with special focuses on the modification strategies including increasing the number of sites with active edges, adjusting the structure of electrocatalysts, and the improvement of electrical conductivity. Then the main preparation methods of HEO electrocatalysts are reviewed. Moreover, theoretical calculations applied in the production of OER catalysts are summarized to guide material design and understand the catalytic mechanism. Finally, this review highlights existing challenges and future design directions of HEO-based OER electrocatalysts.

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“…In particular, the catalytic performance of multicomponent oxides is significantly better than that of single-component material due to the tunable electronic structure. [6][7][8] Nevertheless, the number of transition metal components in conventional oxides is generally limited to three due to the phase separation problem, impeding the effective adjustment of components and electronic structures. [9] Until 2004, the alloying of five or more elements at equimolar or nearly equimolar percentages into a new material, namely high-entropy alloy (HEA), broke the phase separation problem in conventional alloying.…”

Section: Introductionmentioning

confidence: 99%

General Synthesis of Composition‐Tunable High‐Entropy Amorphous Oxides Toward High Efficiency Oxygen Evolution Reaction

Jiang,

Yu,

et al. 2024

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High‐entropy materials have attracted much attention in the electrocatalysis field due to their unique structure, high chemical activity, and compositional tunability. However, the harsh and complex synthetic methods limit the application of such materials. Herein, a universal non‐equilibrium liquid‐phase synthesis strategy is reported to prepare high‐entropy amorphous oxide nanoparticles (HEAO‐NPs), and the composition of HEAO‐NPs can be precisely controlled from tri‐ to ten‐component. The non‐equilibrium synthesis environment provided by an excessively strong reducing agent overcomes the difference in the reduction potentials of various metal ions, resulting in the formation of HEAO‐NPs with a nearly equimolar ratio. The oxygen evolution reaction (OER) performance of HEAO‐NPs is further improved by adjusting the composition and optimizing the electronic structure. The Fe16Co32Ni32Mn10Cu10BOy exhibits a smaller overpotential (only 259 mV at 10 mA cm−2) and higher stability in OER compared with commercial RuO2. The amorphous high‐entropy structure with an optimized concentration of iron makes the binding energy of CoNi shift to a higher direction, promotes the generation of high‐valence active intermediates, and accelerates the OER kinetic process. The HEAO‐NPs have promising application potential in the field of catalysis, biology, and energy storage, and this work provides a general synthesis method for composition‐controllable high‐entropy materials.

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Effect of constituent cations on the electrocatalytic oxygen evolution reaction in high-entropy oxide (Mg0.2Fe0.2Co0.2Ni0.2Cu0.2)O

Cited by 15 publications

References 47 publications

Research Progress of High-Entropy Oxides as Oxygen Evolution Reaction Catalysts

Research Progress of High-Entropy Oxides as Oxygen Evolution Reaction Catalysts

High-Entropy Oxides as Electrocatalysts for the Oxygen Evolution Reaction: A Mini Review

General Synthesis of Composition‐Tunable High‐Entropy Amorphous Oxides Toward High Efficiency Oxygen Evolution Reaction

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