Bimetal‐Organic Framework Derived CoFe<sub>2</sub>O<sub>4</sub>/C Porous Hybrid Nanorod Arrays as High‐Performance Electrocatalysts for Oxygen Evolution Reaction

Lu, Xingwen; Gu, Lin-Fei; Wang, Jia‐Wei; Wu, Jiangxue; Liao, Pei‐Qin; Li, Gao‐Ren

doi:10.1002/adma.201604437

Cited by 723 publications

(395 citation statements)

References 51 publications

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“…The surface molar ratio of Co/Fe in sample was 1.21:1 based on the XPS measurement, which is consistent with the result of ICP analysis. [37,38] A prominent peak of 531.3 eV in the O 1s spectrum (Figure 2c) agrees with metal hydroxides as the dominant active species. [32,36,37] The Co 2p spectrum in Figure 2b can be deconvoluted into two spin-orbit peaks at the binding energies of 781.2 (Co 2p 3/2 ) and 796.8 eV (Co 2p 1/2 ), and the corresponding satellite peaks at 786.1 and 803.1 eV are consistent with the presence of Co 2+ .…”

Section: Electrocatalystssupporting

confidence: 55%

“…XPS spectrum in Figure S6a (Supporting Information) shows same element compositions as determined from EDX measurements. [32,36,37] The Co 2p spectrum in Figure 2b can be deconvoluted into two spin-orbit peaks at the binding energies of 781.2 (Co 2p 3/2 ) and 796.8 eV (Co 2p 1/2 ), and the corresponding satellite peaks at 786.1 and 803.1 eV are consistent with the presence of Co 2+ . In Figure 2a, the XPS spectrum of Fe 2p is featured with two satellite peaks at 718.3 and 733.2 eV, respectively, providing solid evidence to the presence of Fe 3+ .…”

Section: Electrocatalystsmentioning

confidence: 80%

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Iron–Salen Complex and Co²⁺ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Liu

et al. 2019

Advanced Science

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Metal–salen complexes are widely used as catalysts in numerous fundamental organic transformation reactions. Here, CoFe hydroxide/carbon nanohybrid is reported as an efficient oxygen evolution electrocatalyst derived from the in situ formed molecular Fe–salen complexes and Co 2+ ions at a low temperature of 160 °C. It has been evidenced that Fe–salen as a molecular precursor facilitates the confined‐growth of metal hydroxides, while Co 2+ plays a critical role in catalyzing the transformation of organic ligand into nanocarbons and constitutes an essential component for CoFe hydroxide. The resulting Co 1.2 Fe/C hybrid material requires an overpotential of 260 mV at a current density of 10 mA cm −2 with high durability. The high activity is contributed to uniform distribution of CoFe hydroxides on carbon layer and excellent electron conductivity caused by intimate contact between metal and nanocarbon. Given the diversity of molecular precursors, these results represent a promising approach to high‐performance carbon‐based water splitting catalysts.

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Section: Electrocatalystssupporting

confidence: 55%

Section: Electrocatalystsmentioning

confidence: 80%

Iron–Salen Complex and Co²⁺ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Liu

et al. 2019

Advanced Science

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“…In order to determine the relationship between the electronic characteristics of different geometrical sites and the catalytic activities, a series of electrochemical experiment were performed to examine the catalytic performance toward OER. [52][53][54][55] The overpotential raised in the case of further increase in iron dopant (CoFe-0.49 sample). It was worth saying that after further introduction of Fe ions (CoFe-0.49), its performance toward OER evidently decayed due to decreasing Co 2+ (Td) ions in the lattice.…”

Section: Resultsmentioning

confidence: 99%

Unraveling Geometrical Site Confinement in Highly Efficient Iron‐Doped Electrocatalysts toward Oxygen Evolution Reaction

Hung

Hsu

Chang

et al. 2017

Advanced Energy Materials

144

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to develop OER electrocatalysts with a low overpotential in order to scale down the energy expenditure of water electrolysis.To date, noble metal oxides, such as iridium oxide and ruthenium oxide, are regarded as the benchmarked OER electrocatalysts, [10][11][12][13] but their scarcity and high cost hinder them from the wide utilization. [14] For these reasons, it is of the essence to explore earth-abundant substances showing comparable performance as costly noble-metal electrocatalysts. Recently, earth-abundant transition-metalbased materials exhibited high performance and superb stability toward OER, especially for the cobalt and nickel-based oxides/nonoxides. [15][16][17][18][19][20][21][22] Furthermore, various metal dopants would greatly affect the activities and intrinsic attributes. For example, tungsten, chromium, iron, and zinc-doping have been discovered to improve the activities in contrast to pristine metal oxides owing to the optimization of adsorption energy for surface intermediates or the increment of roughness factor. [23][24][25][26][27][28][29] Interestingly, among these elements, iron can commonly perform significant enhancement in catalytic activities toward oxygen evolution reaction as compared to other elements. [30,31] Boettcher's group proposed that Fe ions granted the catalytic activities while Co ions acted as the conductive oxides to transport the charge carriers in an Fe-Co metal oxide system. [32] Friebel et al. conducted a series of operando experiments and calculations to demonstrate that Fe ions in Ni 1-x Fe x OOH system would alter the adsorption energies of OER intermediates over the electrocatalytic surface and thus reduce the overpotential of OER, whereas the formation of low-activity FeOOH declined the resulting activities in the cases of higher Fe content. [33] Howbeit, the behavior of iron based on the material insight was not elaborated. Toward this end, it is crucial to establish the direct relationship between the material characteristics and the catalytic activities.Recently, we reported that the geometrical sites in spinel cobalt oxide served distinct functions. In the case of Co 3 O 4 , the cobalt ions in octahedral site (Co 3+ (Oh) ) contributed to surface double layer capacitance while those in tetrahedral site (Co 2+ (Td) ) were able to adsorb oxygen ions onto the surface for being the active species. [34,35] It suggested that even for the identical Introduction of iron in various catalytic systems has served a crucial function to significantly enhance the catalytic activity toward oxygen evolution reaction (OER), but the relationship between material properties and catalysis is still elusive. In this study, by regulating the distinctive geometric sites in spinel, Fe occupies the octahedral sites (Fe 3+ (Oh) ) and confines Co to the tetrahedral site (Co 2+ (Td) ), resulting in a strikingly high activity (η j = 10 mA cm −2 = 229 mV and η j = 100 mA cm −2 = 281 mV). Further enrichment of Fe ions would occupy the tetrahedral sites to decline the amount of Co 2+ (Td) a...

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“…Co and Fe-based materials have been shown to be excellent OER catalysts and are stable in alkaline solutions. [17][18][19] The proper combination of the ORR and OER electrocatalysts is critical to electrochemical performance. This can be achieved by using a single layer of bifunctional catalysts or by using multiple catalytic layers.…”

mentioning

confidence: 99%

Sequentially Electrodeposited MnO_X/Co-Fe as Bifunctional Electrocatalysts for Rechargeable Zinc-Air Batteries

Xiong

Ivey

2017

J. Electrochem. Soc.

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Manganese oxide (MnOx) and cobalt-iron (Co-Fe) were sequentially electrodeposited onto a gas diffusion layer (GDL) as bifunctional electrocatalysts for rechargeable zinc-air batteries. The fabricated material was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The sequentially deposited MnOx/Co-Fe catalysts, tested using cyclic voltammetry (CV), showed activity for both the oxygen reduction and oxygen evolution reactions (ORR and OER), with better performance than either MnOx or Co-Fe alone. The fabricated material was assembled into a zinc-air battery as the air electrode component for battery cycling tests. The zinc-air battery using MnOx/Co-Fe catalysts exhibited good discharge-recharge performance and a cycling efficiency of 59.6% at 5 mA cm −2 , which is comparable to Pt/C catalysts. In addition, the electrodeposited MnOx/Co-Fe layer showed strong adhesion to the gas diffusion layer (GDL) and was structurally stable throughout 40 h of battery cycling.

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Bimetal‐Organic Framework Derived CoFe₂O₄/C Porous Hybrid Nanorod Arrays as High‐Performance Electrocatalysts for Oxygen Evolution Reaction

Cited by 723 publications

References 51 publications

Iron–Salen Complex and Co²⁺ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Iron–Salen Complex and Co²⁺ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Unraveling Geometrical Site Confinement in Highly Efficient Iron‐Doped Electrocatalysts toward Oxygen Evolution Reaction

Sequentially Electrodeposited MnO_X/Co-Fe as Bifunctional Electrocatalysts for Rechargeable Zinc-Air Batteries

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Bimetal‐Organic Framework Derived CoFe2O4/C Porous Hybrid Nanorod Arrays as High‐Performance Electrocatalysts for Oxygen Evolution Reaction

Cited by 723 publications

References 51 publications

Iron–Salen Complex and Co2+ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Iron–Salen Complex and Co2+ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Unraveling Geometrical Site Confinement in Highly Efficient Iron‐Doped Electrocatalysts toward Oxygen Evolution Reaction

Sequentially Electrodeposited MnOX/Co-Fe as Bifunctional Electrocatalysts for Rechargeable Zinc-Air Batteries

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Bimetal‐Organic Framework Derived CoFe₂O₄/C Porous Hybrid Nanorod Arrays as High‐Performance Electrocatalysts for Oxygen Evolution Reaction

Iron–Salen Complex and Co²⁺ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Iron–Salen Complex and Co²⁺ Ion‐Derived Cobalt–Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst

Sequentially Electrodeposited MnO_X/Co-Fe as Bifunctional Electrocatalysts for Rechargeable Zinc-Air Batteries