Cobalt Sulfide Embedded in Porous Nitrogen-doped Carbon as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

Cao, Xuecheng; Zheng, Xiangjun; Tian, Jing‐Hua; Jin, Chao; Ke, Ke; Yang, Ruizhi

doi:10.1016/j.electacta.2016.01.137

Cited by 134 publications

(64 citation statements)

References 33 publications

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“…In comparison to bulk Co 9 S 8 , nanostructured Co 9 S 8 and its composites could afford more active sites and faster transfer rate of ions/electrons during the electrocatalytic reaction, and thus usually exhibiting enhanced HER and OER activities. [20][21][22][23][24] Currently, several Co 9 S 8 nanostructures (e.g., nanoparticles [25] and nanospheres [26] ) and their composites with carbons (Co 9 S 8 /reduced graphene oxides (RGO), [22] Co 9 S 8 /(N, S, P)-doped carbons, [27] Co 9 S 8 /Fe 3 O 4 / RGO, [23] and Co 9 S 8 /MoS 2 /Carbon fibres [25] ) have been reported. For example, Co 9 S 8 /N,P-carbon powder nanocomposites prepared by molten-salt calcination method at 900 °C exhibited an HER overpotential of 261 mV at 10 mA cm −2 in alkaline medium.…”

Section: Doi: 101002/advs201700772mentioning

confidence: 99%

Hollow TiO₂@Co₉S₈ Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

et al. 2017

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water splitting is recognized as a highly potential technology to convert electricity into environment friendly and renewable chemical fuels (hydrogen and oxygen). [1][2][3] The cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) depend heavily on the development of cost-effective high-performance electrocatalysts. [4,5] Currently, platinum (Pt)/Pt-based alloy and iridium/ruthenium oxides (IrO 2 /RuO 2 ) are considered as the most promising electrocatalysts for HER and OER, respectively, but their scarcity, high cost, and compromised stability hinder their widespread applications. [6,7] Additionally, the best working situation for those OER and HER catalysts is often mismatchable since OER preferably takes place in alkaline or neutral solution while HER in acidic medium. [8,9] This would cause compromised performance for overall water splitting. For instance, the commercial alkaline electrolyzers require high cell voltages (1.8-2.0 V) to drive water splitting, [10] far ahead of the theoretical value of ≈1.23 V owing to high overpotentials on the sluggish of OER and HER. Therefore, it is highly desirable to explore alternative high-performance and low-cost bifunctional OER/HER electrocatalysts for overall water splitting. [11][12][13][14][15] Over the past decades, great progress has been achieved on the development of non-noble metal-based electrocatalysts for both OER and HER. Various nonprecious metal oxides, [9] sulfides, [16] selenides, [17] phosphides, and nitrides [18,19] have been exploited. Among these electrocatalysts, cobalt sulfide (Co 9 S 8 ) is regarded as an attractive electrocatalyst for water splitting due to its high catalytic activity for HER and OER simultaneously, and excellent electrochemical stability. In comparison to bulk Co 9 S 8 , nanostructured Co 9 S 8 and its composites could afford more active sites and faster transfer rate of ions/electrons during the electrocatalytic reaction, and thus usually exhibiting enhanced HER and OER activities. [20][21][22][23][24] Currently, several Co 9 S 8 nanostructures (e.g., nanoparticles [25] and nanospheres [26] ) and their composites with carbons (Co 9 S 8 /reduced graphene oxides (RGO), [22] Co 9 S 8 /(N, S, P)-doped carbons, [27] Co 9 S 8 /Fe 3 O 4 / RGO, [23] and Co 9 S 8 /MoS 2 /Carbon fibres [25] ) have been reported. For example, Co 9 S 8 /N,P-carbon powder nanocomposites prepared by molten-salt calcination method at 900 °C exhibited an HER overpotential of 261 mV at 10 mA cm −2 in alkaline medium. [20] N-Co 9 S 8 /graphene nanocomposites was achieved Designing ever more efficient and cost-effective bifunctional electrocatalysts for oxygen/hydrogen evolution reactions (OER/HER) is greatly vital and challenging. Here, a new type of binder-free hollow TiO 2 @Co 9 S 8 core-branch arrays is developed as highly active OER and HER electrocatalysts for stable overall water splitting. Hollow core-branch arrays of TiO 2 @Co 9 S 8 are readily realized by the rational combination of crosslinked Co 9 S 8 nanoflakes on ...

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Section: Doi: 101002/advs201700772mentioning

confidence: 99%

Hollow TiO₂@Co₉S₈ Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

et al. 2017

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“…The excellent OER activity of Co@Co 9 S 8 electrodes can be ascribed to the following factors: on the one hand, Co 9 S 8 has intrinsically high catalytic activity for OER. Recent reports have demonstrated that Co 9 S 8 has a favorable electronic configuration that facilitates the required level of chemical interaction between the O atoms in water molecules and the empty anti‐bonding states in metal cations during the initial stage of the OER . To substantiate that the OER catalytic activity indeed results from Co 9 S 8 , we managed to eliminate Co 9 S 8 particles from the CF current collector using an ultrasonicating probe, and measured the OER activity of Co 9 S 8 particle spread on a glassy carbon substrate (Figure S12).…”

Section: Resultsmentioning

confidence: 99%

One‐Step Fabrication of Monolithic Electrodes Comprising Co₉S₈ Particles Supported on Cobalt Foam for Efficient and Durable Oxygen Evolution Reaction

Xiong

Zhang

Thalluri

et al. 2017

Chemistry A European J

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A very easy and cost-effective approach to the fabrication of monolithic Co S water oxidation electrodes (Co@Co S ), fabricated by one-step hydrothermal treatment of commercially available cobalt foam in the presence of thiourea, is reported. The morphology, crystal structure, microstructure, and composition of as-fabricated Co@Co S electrodes were examined by using scanning electron microscopy (SEM), powder X-ray diffractometry (XRD), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS), and their electrochemical properties were investigated by cyclic voltammetry (CV), chronopotentiometry (CP), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). When used to catalyze the oxygen evolution reaction (OER) in alkaline solution, the Co@Co S electrode with an optimal Co S loading exhibits outstanding catalytic activity, requiring a low overpotential of 350 mV to deliver an anodic current density of 10 mA cm and showing fast kinetics for OER with a small Tafel slope (55 mV dec ) and charge-transfer resistance (0.44 Ω cm ), which outperforms many sulfide-based OER catalysts and some state-of-the-art noble metal catalysts recently reported in the literature. Importantly, the electrodes show excellent long-term stability, and are capable of operating at both a low current density and a high current density relevant to industrial water electrolysis up to 100 hours.

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“…The Co 9 S 8 /CNFs membrane displays two peaks located at 29.8° and 51.8°, and all of the diffraction peaks can be readily indexed to the cubic Co 9 S 8 phase (JCPDS no. 19‐0364, space group: Fm3m ) . XRD results indicate the successful formation of the Co/CNFs, Co 3 O 4 /CNFs, and Co 9 S 8 /CNFs membrane.…”

Section: Resultsmentioning

confidence: 63%

A Facile Strategy to Synthesize Cobalt‐Based Self‐Supported Material for Electrocatalytic Water Splitting

Zhu

et al. 2017

Part & Part Syst Charact

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Designing and developing active, robust, and noble‐metal‐free catalysts with superior stability for electrocatalytic water splitting is of critical importance but remains a grand challenge. Here, a facile strategy is provided to synthesize a series of Co‐based self‐supported electrode materials by combining electrospinning and chemical vapor deposition (CVD) technologies. The Co, Co3O4, Co9S8 nanoparticles (NPs) are formed in situ simultaneously with the formation of carbon nanofibers (CNFs) during the CVD process, respectively. The Co‐based NPs are uniformly distributed through the CNFs and they can be directly used as the electrode materials for hydrogen evolution reaction (HER) in acid and oxygen evolution reaction (OER) in alkaline. The Co9S8/CNFs membrane exhibits the best HER activity with overpotential of 165 mV at j = 10 mA cm−2 and Tafel slope of 83 mV dec−1 and OER activity with overpotential of 230 mV at j = 10 mA cm−2 and Tafel slope of 72 mV dec−1. The onion‐like graphitic layers formed around the NPs not only improve the electrical conductivity of the electrode but also prevent the separation of the NPs from the carbon matrix as well as the aggregation.

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Cobalt Sulfide Embedded in Porous Nitrogen-doped Carbon as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

Cited by 134 publications

References 33 publications

Hollow TiO₂@Co₉S₈ Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

Hollow TiO₂@Co₉S₈ Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

One‐Step Fabrication of Monolithic Electrodes Comprising Co₉S₈ Particles Supported on Cobalt Foam for Efficient and Durable Oxygen Evolution Reaction

A Facile Strategy to Synthesize Cobalt‐Based Self‐Supported Material for Electrocatalytic Water Splitting

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Cobalt Sulfide Embedded in Porous Nitrogen-doped Carbon as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

Cited by 134 publications

References 33 publications

Hollow TiO2@Co9S8 Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

Hollow TiO2@Co9S8 Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

One‐Step Fabrication of Monolithic Electrodes Comprising Co9S8 Particles Supported on Cobalt Foam for Efficient and Durable Oxygen Evolution Reaction

A Facile Strategy to Synthesize Cobalt‐Based Self‐Supported Material for Electrocatalytic Water Splitting

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Hollow TiO₂@Co₉S₈ Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

Hollow TiO₂@Co₉S₈ Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

One‐Step Fabrication of Monolithic Electrodes Comprising Co₉S₈ Particles Supported on Cobalt Foam for Efficient and Durable Oxygen Evolution Reaction