Intrinsic Electrocatalytic Activity for Oxygen Evolution of Crystalline 3d‐Transition Metal Layered Double Hydroxides

including solar, wind, hydro, and biofuel, are highly desired to reduce our reliance on fossil fuels. However, according to the data provided by International Energy Agency, the global energy demand is 120 Mtoe in 2019, most (80%) of which was derived from fossil fuels (coal, natural gas, oil), leading to a huge CO 2 emission (33Gt in 2019). [1][2][3] One of the difficulties hindering the widespread use of these renewable energy sources is their intermittent and unpredictable nature. [4,5] Electrochemical reaction, a promising strategy for converting intermittent electricity into chemical energy, can produce a wide variety of important fuels and chemical feedstock, including hydrogen, hydrocarbons and ammonia. [6][7][8] The feedstocks for these productions obtained from electrochemical reactions can be offered by abundant and universal source, such as water, carbon dioxide and nitrogen. In last decades, due to the net-zero carbon emission features, electrochemical reactions have initiated extensive investigations based on water splitting reaction, nitrogen reduction reaction (NRR) and carbon dioxide reduction reaction. [9][10][11][12] In these green technologies, electrocatalytic oxygen evolution reaction (OER), a core reaction of these process, has a direct impact on device efficiency and cost effectiveness (Figure 1). [13,14] However, OER involves multistep four-electron transferring steps associated with OH breaking and OO formations, thus suffering from sluggish kinetics and requiring a high energy loss (high potential). Therefore, efficient and stable OER electrocatalysts are required to make these renewable energy storage/conversion processes to be viable and scalable technologies. [15,16,221,222] The OER catalysts can be classified into two categories: [17,18] molecular catalysts for homogeneous system and solid catalysts for heterogeneous system. In the homogeneous catalytic system, the molecular catalysts and the electrolyte are in solution, and the OER takes place in the liquid phase. The performance of molecular OER catalysts can be explained and understood at a molecular level by many relatively simple spectroscopic physicochemical techniques. Based on the mechanistic understanding at a molecular level, their geometric and electronic properties are much easier to be fine-tuned to achieve optimum performance by careful selection of the metal ion and ligand environment. Despite all these advantages, molecular catalysts are still not appropriate to be used in practical Electrocatalytic oxygen evolution reaction (OER), an important electrode reaction in electrocatalytic and photoelectrochemical cells for a carbonfree energy cycle, has attracted considerable attention in the last few years. Metal oxides have been considered as good candidates for electrocatalytic OER because they can be easily synthesized and are relatively stable during the OER process. However, inevitable structural variations still occur to them due to the complex reaction steps and harsh working conditions of OER, thus impending the ...

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Section: Perovskitesmentioning

confidence: 99%

Structural Variations of Metal Oxide‐Based Electrocatalysts for Oxygen Evolution Reaction

et al. 2021

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“…Among all the LDHs, there are abundant research studies about CoFe-based materials such as CoFe-layered double hydroxides (LDHs). [15] The CoFe-LDH shows high electrocatalytic activity, which is superior to those of corresponding Co(OH) 2 and the mixed phase samples of Co(OH) 2 and FeOOH. [16] For example, CoFe-LDH electrocatalysts exhibit great prospects in water oxidation in virtue of the synergistic effect between Co and Fe ions.…”

Section: Introductionmentioning

confidence: 90%

Controllable Modulation of Defects for Layered Double Hydroxide Nanosheets by Altering Intercalation Anions for Efficient Electrooxidation Catalysis

Lai

Wang

Sun

et al. 2021

Chemistry An Asian Journal

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Hydrazine (N 2 H 4 ) is considered as one of the most potential energy storage materials in liquid fuel cells, as it contains high energy and power density, and the highefficiency oxidation of N 2 H 4 in fuel cells has drawn great attention. However, the most used catalysts are expensive noble metal catalysts, thus the development of highly efficient non-noble metal catalysts is crucial to reduce the cost of hydrazine oxidation in practical industry. Herein, we synthesized a series of CoFe-layered double hydroxides (CoFe-LDHs) intercalated with different anions via a simple one-step co-precipitation method for the electrooxidation of hydrazine. Through altering the intercalated anions of CoFe-LDHs, the defects and the electronic structure can be well controlled, and the catalytic performance for the electrooxidation of hydrazine were well promoted by using NO 3 À intercalated into CoFe-LDH compared with other anions (like Cl À , BO 3 3À , CO 3 2À ). This work developed a series of hydrazine electrooxidation catalysts and established the relationship between the intercalated anions, the fine structure of the catalyst and the electrocatalytic performance.

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“…11, which likewise holds true for alkaline conditions, also impacts the ORR [42] in the same fashion. While 3.2 eV refers to the most often reported scaling-relation offset, also intercepts deviating from this value have been put forth in the literature, such as 2.8 eV for various metal oxides, [43] 2.93 eV for transition-metal oxides [44] or RuO 2based electrocatalysts, [45] 2.95 eV for NiFe and CoFe layered double hydroxides, [46,47] and about 3 eV by considering the solvent interactions in the work of Man et al. [48] Independent of its value, the scaling-relation offset restrains the parameter space of adsorption free energies in the OER and ORR both.…”

Section: Methods Bifunctional Index From Cyclic Voltammetrymentioning

confidence: 99%

“…This result refers to a SRI of 2.9 eV, which is compatible with recent theoretical reports. [44][45][46][47] Yet, experimentally synthesized materials are still far away from such bifunctional performance according to our literature survey (cf. Table 3).…”

Section: Chemelectrochemmentioning

confidence: 99%

Method to Determine the Bifunctional Index for the Oxygen Electrocatalysis from Theory

Razzaq

Exner

2022

ChemElectroChem

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Metal‐air batteries are encountered as a promising solution for energy storage due to their high energy density, cost effectiveness, and environmental benefits. Yet, the application of metal‐air batteries in practice is still not mature, which is also related to the bifunctional oxygen electrocatalysis at the cathode, comprising the oxygen reduction (ORR) and oxygen evolution (OER) reactions during discharge and charge of the battery, respectively. Experimentally, the performance of electrocatalysts in the OER and ORR is described by bifunctional index (BI), but, so far, there is no direct approach to capture the BI on the atomic scale. Herein, we present a method to ascertain the BI from ab initio theory, thereby combining a data‐driven methodology with thermodynamic considerations and microkinetic modeling as a function of the applied overpotential. Our approach allows deriving the BI from simple adsorption free energies, which are easily accessible to electronic structure theory in the density functional theory (DFT) approximation. We outline how our methodology may steer the design of efficient bifunctional catalysts on the atomic scale.

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Intrinsic Electrocatalytic Activity for Oxygen Evolution of Crystalline 3d‐Transition Metal Layered Double Hydroxides

Cited by 209 publications

References 60 publications

Structural Variations of Metal Oxide‐Based Electrocatalysts for Oxygen Evolution Reaction

Structural Variations of Metal Oxide‐Based Electrocatalysts for Oxygen Evolution Reaction

Controllable Modulation of Defects for Layered Double Hydroxide Nanosheets by Altering Intercalation Anions for Efficient Electrooxidation Catalysis

Method to Determine the Bifunctional Index for the Oxygen Electrocatalysis from Theory

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