A CoFe2O4/graphene nanohybrid as an efficient bi-functional electrocatalyst for oxygen reduction and oxygen evolution

Bian, Weiyong; Yang, Zhijuan; Strasser, Peter; Yang, Ruizhi

doi:10.1016/j.jpowsour.2013.11.024

Cited by 311 publications

(199 citation statements)

References 40 publications

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“…Also, the better linear relationship of Koutecky-Levich (K-L) plots was observed for AgNCs/rGO_AA electrode at various potentials than that of the AgNCs/rGO_NaBH 4 modified electrodes (Figure 5a , and 5B ) which suggesting the slope of those plots and corresponding n values could be similar for ORR and represents first order kinetics with respect to O 2 . 64 Therefore, the n values per O 2 involved in the ORR at both AgNCs/rGO electrodes were calculated again by the K-L Equation 4 17,62,64 which are similar to the calculation by CVs earlier (Figure 5 insets). Indicating the ORR proceeds via a four-electron (4e -) pathway at AgNCs/rGO_AA than AgNCs/rGO_NaBH 4 electrode.…”

Section: 55supporting

confidence: 62%

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Ahmed

Lee

Kim

2016

J. Electrochem. Soc.

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The silver nanocrystals (AgNCs) anchored on graphene oxide (GO) catalysts have been synthesized by a facile chemical reduction and nontemplate method using ascorbic acid (AA) as reducing agent and have successfully employed as a cathode catalyst for oxygen reduction reaction (ORR) in direct alkaline fuel cells (DAFCs). The morphological characterizations demonstrate that the AgNCs have crystalline form and grafted onto reduced graphene oxide (AgNCs/rGO_AA). Comparatively better dispersion and higher population of AgNCs have observed on AA treated AgNCs/rGO than NaBH 4 which is known as conventional reducing agent. The electrochemical catalysis in 0.1 M KOH electrolyte has demonstrated that the AgNCs/rGO_AA has an excellent electrocatalytic activity for ORR in alkaline media compared to the other tested electrodes. Particularly, it shows 40% higher mass activity with large specific activity against 20 wt% Pt/C with faster electron transfer rate per O 2 . Moreover, the reaction kinetic parameters have confirmed that the ORR at AgNCs/rGO_AA catalyst not only follows a 4e -process with lowering H 2 O 2 formation but also proceeds on with good stability and fuel selectivity in DAFCs. The oxygen reduction reaction (ORR) is an interesting research area and already attracted widespread attention of researches from all over the world because of its important role in the application of energy storage and conversion devices, such as fuel cells (FCs) and metal−air batteries in alkaline media.1-4 Due to superior energy conversion efficiency and potential for providing clean energy, FCs are in the main attention as next generation energy sources. 5,6 As the FCs consists of anode and cathode electrodes, the greatest effect on the performance of FCs is the oxidation/reduction reaction kinetics occurring at the respective electrodes. Unfortunately, the sluggish kinetic rate of ORR at the cathode is the main obligation to be applied in industry. 6 Typically, the platinum (Pt) and/or Pt-based materials are known as the most efficient electrocatalyst in the cathode for ORR catalysis [7][8][9][10] but unfortunately, the Pt-based materials have faced many troubles such as its susceptibility to time dependent drift and CO poisoning, 11,12 slow electron-transfer kinetics, 13 high costs, limited supply, 14 and poor durability. 15 For those reasons, Pt has hindered the widespread commercialization of FCs technology. To overcome the cost challenges, significant efforts have focused on the development of alternative non-Pt catalysts that are based on mainly non-precious metals and/or various heteroatom-doped carbonaceous materials. [16][17][18] Among the non-Pt metal catalysts studied, silver (Ag)-based carbon nanomaterials have been explored as promising candidates with higher activity and stability in alkaline medium recently. [19][20][21][22] According to previous reports, the Ag is an ideal alternative of Pt because it is not only abundantly available in nature and much cheaper but also higher electrical and thermal conductive than Pt....

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Section: 55supporting

confidence: 62%

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Ahmed

Lee

Kim

2016

J. Electrochem. Soc.

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“…It was able to fully combine the advantages of both CoFe 2 O 4 nanoparticles and N-doped reduced graphene oxide, achieving a more positive ORR onset potential than CoFe 2 O 4 loading on nondoped reduced graphene oxide in the previous literature. [ 40 ] Moreover, the multimetal oxide shows better catalytic activity to ORR than the single metal oxide does. The fi nal product of CoFe 2 O 4 /NG annealed at 500 °C exhibited a comparable catalytic activity as commercial Pt/C with a preferential four-electron pathway in the ORR, while it outperformed Pt/C in terms of stability and resistance to CO poisoning and methanol crossover.…”

Section: Introductionmentioning

confidence: 99%

Well‐Combined Magnetically Separable Hybrid Cobalt Ferrite/Nitrogen‐Doped Graphene as Efficient Catalyst with Superior Performance for Oxygen Reduction Reaction

Liu

Hao

Lei

et al. 2015

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Catalysts with low-cost, high activity and stability toward oxygen reduction reaction (ORR) are extremely desirable, but its development still remains a great challenge. Here, a novel magnetically separable hybrid of multimetal oxide, cobalt ferrite (CoFe2O4), anchored on nitrogen-doped reduced graphene oxide (CoFe2O4/NG) is prepared via a facile solvothermal method followed by calcination at 500 °C. The structure of CoFe2O4/NG and the interaction of both components are analyzed by several techniques. The possible formation of Co/Fe-N interaction in the CoFe2O4/NG catalyst is found. As a result, the well-combination of CoFe2O4 nanoparticles with NG and its improved crystallinity lead to a synergistic and efficient catalyst with high performance to ORR through a four-electron-transfer process in alkaline medium. The CoFe2O4/NG exhibits particularly comparable catalytic activity as commercial Pt/C catalyst, and superior stability against methanol oxidation and CO poisoning. Meanwhile, it has been proved that both nitrogen doping and the spinel structure of CoFe2O4 can have a significant contribution to the catalytic activity by contrast experiments. Multimetal oxide hybrid demonstrates better catalysis to ORR than a single metal oxide hybrid. All results make the low-cost and magnetically separable CoFe2O4/NG a promising alternative for costly platinum-based ORR catalyst in fuel cells and metal-air batteries.

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“…This can possibly be attributed mainly to the hierarchical mesoporous structure of the RC matrix and the strong coupling and synergistic effects between CFO and RC. Based on the obtained ORR and OER activities, the CFO/RC-400 composite was also found to outperform other carbon-spinel oxide composite catalysts such as NiCo 2 O 4 / grapheme [139], CoFe 2 O 4 /grapheme [140], and CoFe 2 O 4 / biocarbon [141], suggesting that ordered mesoporous carbon rods are more suitable for spinel oxide nanoparticle loading to improve ORR and OER than other carbon matrixes such as CNTs, graphene, and biocarbon materials.…”

mentioning

confidence: 93%

A Review of Carbon-Composited Materials as Air-Electrode Bifunctional Electrocatalysts for Metal–Air Batteries

Wang

Fang

Zhang

et al. 2018

Electrochem. Energ. Rev.

178

101

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Metal-air batteries (MABs), particularly rechargeable MABs, have gained renewed interests as a potential energy storage/conversion solution due to their high specific energy, low cost, and safety. The development of MABs has, however, been considerably hampered by its relatively low rate capability and its lack of efficient and stable air catalysts in which the former stems mainly from the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) and the latter stems from the corrosion/oxidation of carbon materials in the presence of oxygen and high electrode potentials. In this review, various carbon-composited bifunctional electrocatalysts are reviewed to summarize progresses in the enhancement of ORR/OER and durability induced by the synergistic effects between carbon and other component(s). Catalyst mechanisms of the reaction processes and associated performance enhancements as well as technical challenges hindering commercialization are also analyzed. To facilitate further research and development, several research directions for overcoming these challenges are also proposed.

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A CoFe2O4/graphene nanohybrid as an efficient bi-functional electrocatalyst for oxygen reduction and oxygen evolution

Cited by 311 publications

References 40 publications

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Well‐Combined Magnetically Separable Hybrid Cobalt Ferrite/Nitrogen‐Doped Graphene as Efficient Catalyst with Superior Performance for Oxygen Reduction Reaction

A Review of Carbon-Composited Materials as Air-Electrode Bifunctional Electrocatalysts for Metal–Air Batteries

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