The art of balance: Engineering of structure defects and electrical conductivity of α-MnO2 for oxygen reduction reaction

Lan, Bang; Zheng, Xiaoying; Cheng, Gao; Han, Jiaxi; Li, Wanping; Sun, Ming; Yu, Lin

doi:10.1016/j.electacta.2018.06.195

Cited by 55 publications

(28 citation statements)

References 55 publications

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“…Based on the ORR and OER result, the NiCo 2 O 4 (CH 3 OH) exhibits superior electrochemical performance among the prepared three catalysts. This can be understood by considering the below facts: (1) according to BET and BJH result, the NiCo 2 O 4 (CH 3 OH) has the largest BET surface area and pore size diameter, and such characteristics can facilitate better oxygen diffusion and electron transfer than its counterparts; (2) The defects such as oxygen defects play a key role in the ORR/OER activities . From the result of the O 1s peak fitting, NiCo 2 O 4 (CH 3 OH) possesses the biggest amount of defect oxygen, which dominates the ORR/OER process, contributing a lot to its outstanding electrochemical activity; (3) the electrochemical surface area (ECSA).…”

Section: Resultsmentioning

confidence: 99%

Shape‐Controlled Synthesis of NiCo₂O₄‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Cheng

Zhou

et al. 2019

ChemElectroChem

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The engineering of morphology and surface structure of electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is an effective strategy to improve their performance. Herein, we synthesized NiCo2O4 catalysts with different shape by controlling the reaction solvent and studied their morphology‐dependent ORR/OER activities by various characterizations and electrochemical measurements. The NiCo2O4 prepared using methanol as solvent displays three‐dimensional (3D) hierarchical structure composed of interconnected nanosheets, and exhibits the best ORR/OER performance (a half‐wave potential of 0.78 V for ORR and an overpotential of 381 mV for OER). When used as catalyst for a rechargeable Zn‐air battery, it possesses a peak power density of 125.3 mW cm−2 with relatively superior durability.

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Section: Resultsmentioning

confidence: 99%

Shape‐Controlled Synthesis of NiCo₂O₄‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Cheng

Zhou

et al. 2019

ChemElectroChem

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“…Metal oxides, including Mn, Co, Ni, and Fe oxides, are considered feasible for bifunctional oxygen catalysis because of their intrinsic activity, low cost, environmental friendliness, earth abundance, and structural flexibility . For instance, manganese oxides (MnO x ) can be obtained in the form of Mn 5 O 8 , Mn 3 O 4 , Mn 2 O 3 , MnO 2 , MnO, MnOOH, etc ., as well as in various morphologies (e. g., urchin‐like, star‐like, nanoballs, nanowires, nanorods, nanotubes, nanosheets, nanoflowers, and hollow spheres, as shown in Figure ), which all show considerable catalytic activities in alkaline media . Such compositional and structural flexibility of metal oxides provides a great opportunity to regulate their electrocatalytic performances.…”

Section: Carbon‐based Compositesmentioning

confidence: 99%

Recent Advances in Carbon‐Based Bifunctional Oxygen Catalysts for Zinc‐Air Batteries

Liu

Tong

Yan

et al. 2019

Batteries & Supercaps

130

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air batteries (ZABs) have recently received tremendous research attention due to their high theoretical energy densities. However, current ZABs suffer from poor energy efficiency and cyclability, mainly owing to the sluggish kinetics of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) on the air electrode. Therefore, rational design of efficient bifunctional oxygen electrocatalysts with high activity and stability is essential for improving battery performance. Carbon-based nanomaterials are promising candidates for bifunctional oxygen catalysis. In this review, we present the latest development of carbon-based bifunctional electrocatalysts for ZABs. Firstly, the related reaction mechanisms of bifunctional ORR/OER catalysts are introduced. Then, the recent advances in developing carbon-based bifunctional catalysts with tailored structure and promising catalytic performance are introduced following the regulation strategies, e. g., heteroatom doping, defect engineering, and/or hybridizing with other active materials. Finally, the key challenges and perspectives of advanced ZABs are provided to better shed light on future research. . This review aims to provide timely information of the carbon-based bifunctional oxygen catalysts for researchers and to shed light on the future development of high-performance catalysts and ZABs. 2 3 4 5 6 7 8

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“…[15] Especially MnO 2 , which can occur in various polymorphs depending on its crystallographic structure, Mn oxidation state and Mn/O stoichiometry within the compound, has gained significant interest and is still the focus of research and development as alternative to precious metal based catalysts. [16] To date, the electrocatalytic activity of MnO 2 for the ORR [17][18][19][20] and OER [3,9,[21][22][23] has already been proven. More important, Meng and co-workers prepared an array of MnO 2 catalyst materials by utilizing various synthesis routes and studied the effect of crystallographic structure for catalysing ORR and OER.…”

Section: Introductionmentioning

confidence: 99%

Bifunctional α‐MnO₂ and Co₃O₄ Catalyst for Oxygen Electrocatalysis in Alkaline Solution

et al. 2020

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This work is dedicated to Prof. Monika Willert-Porada. We kindly would like to thank her for her contribution to the project and her support. Low cost and abundant catalysts demonstrating high activity and stability towards the oxygen reactions, i. e., the oxygen reduction (ORR) and oxygen evolution reaction (OER), are crucial for the development of electrically rechargeable zinc-air batteries. Herein, the facile synthesis and systematic characterisation of two highly active and stable oxygen electrocatalysts, i. e., high surface area α-MnO 2 microspheres and nanoparticulate Co 3 O 4 , are reported. α-MnO 2 exhibits low half-wave potential and potential of À 0.197 and À 0.226 V (vs. Ag/AgCl) at À 3 mA cm À 2 , respectively, that are only marginally higher compared to commercial Pt/C (E 1/2 = À 0.161 V, E j =-3 = À 0.171 V) for ORR. Meanwhile, Co 3 O 4 needs a potential of 0.601 V (vs. Ag/ AgCl) to drive 10 mA cm À 2 being competitive to commercial Ir/C (E j = 10 = 0.60 V) for OER. In order to create a bifunctional catalyst, two approaches were pursued: i) Co 3 O 4 nanoparticles were homogeneously grown on the surface of α-MnO 2 microspheres yielding a radial hybrid composite catalyst material in the form of a core (α-MnO 2) shell (Co 3 O 4) structure and ii), much simpler, individual α-MnO 2 microspheres and Co 3 O 4 nanoparticles were physically mixed in a powder blend. The powder blend demonstrates superior overall bifunctional catalytic properties such that the individual catalysts still dominate their respective oxygen reaction and, due to synergistic interactions between both catalysts, an improved ORR activity could be achieved.

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The art of balance: Engineering of structure defects and electrical conductivity of α-MnO2 for oxygen reduction reaction

Cited by 55 publications

References 55 publications

Shape‐Controlled Synthesis of NiCo₂O₄‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Shape‐Controlled Synthesis of NiCo₂O₄‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Recent Advances in Carbon‐Based Bifunctional Oxygen Catalysts for Zinc‐Air Batteries

Bifunctional α‐MnO₂ and Co₃O₄ Catalyst for Oxygen Electrocatalysis in Alkaline Solution

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The art of balance: Engineering of structure defects and electrical conductivity of α-MnO2 for oxygen reduction reaction

Cited by 55 publications

References 55 publications

Shape‐Controlled Synthesis of NiCo2O4‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Shape‐Controlled Synthesis of NiCo2O4‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Recent Advances in Carbon‐Based Bifunctional Oxygen Catalysts for Zinc‐Air Batteries

Bifunctional α‐MnO2 and Co3O4 Catalyst for Oxygen Electrocatalysis in Alkaline Solution

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About

Shape‐Controlled Synthesis of NiCo₂O₄‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Shape‐Controlled Synthesis of NiCo₂O₄‐rGO as Bifunctional Electrocatalyst for Zn‐Air Battery

Bifunctional α‐MnO₂ and Co₃O₄ Catalyst for Oxygen Electrocatalysis in Alkaline Solution