Single‐Shell Carbon‐Encapsulated Iron Nanoparticles: Synthesis and High Electrocatalytic Activity for Hydrogen Evolution Reaction

Tavakkoli, Mohammad; Kallio, Tanja; Reynaud, Olivier; Nasibulin, Albert G.; Johans, Christoffer; Sainio, Jani; Jiang, Hua; Kauppinen, Esko I.; Laasonen, Kari

doi:10.1002/ange.201411450

Cited by 71 publications

(41 citation statements)

References 43 publications

(29 reference statements)

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“…Furthermore, our calculations predicted that a thinner layer would be better for ORR in M@N-C nanoparticles. 27,44,45 These tendencies are consistent with previous reports that the thinner layer of carbon leads to higher activity in the FeCo alloy catalyst encapsulated in pod-like carbon nanotubes. Moreover, a particle encapsulated with a single layer of carbon has also been used as a HER and OER catalyst with superior activity.…”

Section: Thickness Of Carbon Shells For Orr Activitysupporting

confidence: 91%

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

et al. 2016

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The identification and development of efficient catalysts made of non-precious materials for oxygen reduction reaction (ORR) are essential for the successful operation of a wide range of energy devices. This study provides evidence that earth-abundant nanoparticles of transition metals encapsulated in a nitrogen-doped carbon shell (M@N-C, M = Fe, Co, Ni, Cu or Fe alloys) are promising catalysts in acidic solutions. By density functional theory calculations and experimental validations, we quantitatively propose a method of tuning the ORR activity of M@N-C by controlling the nitrogen-doping level, the thickness of the N-C shells and binary alloying. FeCo@N-C/KB was chosen as the best ORR catalyst because of its onset and half-wave potentials of 0.92 and 0.74 V vs a reversible hydrogen electrode (RHE), respectively, and its excellent durability. Furthermore, FeCo@N-C/KB possesses a high activity for the hydrogen evolution reaction (HER; − 0.24 V vs RHE at − 10 mA cm − 2 ), thus demonstrating that it is a good bi-functional ORR and HER catalyst in acidic media.

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Section: Thickness Of Carbon Shells For Orr Activitysupporting

confidence: 91%

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

et al. 2016

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“…The XPS results for Co/AC only revealed the binding energy of Co II species, which demonstrated that surface‐exposed Co NPs were facile to oxidize. Moreover, the binding energy of encapsulated metallic cobalt is higher than that of bulk Co NPs (778.0 eV) by 0.4 eV; this is consistent with charge transfer from the encapsulated Co metal to the carbon shells; thus the electrical levels of cobalt and carbon atoms were modified. It has been reported that the interaction of N‐doped carbon nanotubes (N‐CNTs) and confined Co could increase the density of states (DOS) near the Fermi level and reduce the work function ( Φ ), which is beneficial for donating electrons from the surface of N‐CNTs to surface‐adsorbed molecular oxygen, thereby enabling the Co 4 @CNTs to be an outstanding electrocatalytic catalyst in the ORR .…”

Section: Resultssupporting

confidence: 55%

Activation of Molecular Oxygen Using Durable Cobalt Encapsulated with Nitrogen‐Doped Graphitic Carbon Shells for Aerobic Oxidation of Lignin‐Derived Alcohols

Sun

Luo

et al. 2018

Chemistry A European J

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It has long been a challenge for activating O by transition-metal nanocatalysts, which might lose activity due to strong tendency for oxidation. Herein, O could be activated by durable encapsulated cobalt nanoparticles (NPs) with N-doped graphitic carbon shells (Co@N-C), but not by encapsulated cobalt NPs with graphitic carbon, exposed cobalt NPs supported on activated carbon, or N-doped carbon. Electron paramagnetic resonance, real-time in situ FTIR spectroscopy, and mass spectrometry measurements demonstrated the generation of the highly active superoxide radical, O . This unique ability enables Co@N-C to afford an excellent catalytic performance in model aerobic oxidation of monomeric lignin-derived alcohols. Further analysis elucidated that encapsulated cobalt and nitrogen-doped graphitic carbon might contribute to the capacity through influencing the electronic properties of outer layers. Moreover, through isolation by N-doped graphitic carbon shells, the inner metallic cobalt NPs are inaccessible in term of either alcohols or oxygenated products, and a distinctive resistance to leaching and agglomeration has been achieved.

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“…For instances, Ni−Sn@C core/shell structure was synthesized by combining sol−gel, chemical vapor deposition (CVD) and etching processes 63 . Tavakkoli et al 64 used single-walled CNTs as the carbon shell to encapsulate Fe nanoparticles by CVD technique (Fig. This core/shell catalyst had a high conductivity and large active surface area and exhibited good electrocatalytic activity toward HER.…”

Section: Noble Metal-free Compositesmentioning

confidence: 99%

Nanostructured catalysts for electrochemical water splitting: current state and prospects

et al. 2016

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Hydrogen is an ideal candidate for the replacement of fossil fuels in the future due to its zero emission of the carbonaceous species during its utilization. Water electrolysis is a dependable link of primary renewable energy and stable hydrogen energy. In this work, the fundamentals of water electrolysis, current popular electrocatalysts developed for cathodic hydrogen evolution reaction (HER) and anodic oxygen evoltion reacion (OER) in liquid electrolyte water electrolysis are reviewed. The main HER catalysts include noble metals, non-noble metal and composites, noble metal-free alloy, metal carbides, chalcogenides, phosphides and metal-free materials while the OER catalysts are focused on efficient Co-based, Ni-based materials and layered double hydroxides (LDH) materials. The strategies to improve catalytic activity, long-term durability and endurance to electrochemical erosions are introduced. The main challenges and future prospects for the further development of electrodes for water electrolysis are discussed. It is expected to give a guidance to the development of novel nanostructured electrocatalysts with low-cost for the electrochemical water splitting.

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Single‐Shell Carbon‐Encapsulated Iron Nanoparticles: Synthesis and High Electrocatalytic Activity for Hydrogen Evolution Reaction

Cited by 71 publications

References 43 publications

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

Towards a comprehensive understanding of FeCo coated with N-doped carbon as a stable bi-functional catalyst in acidic media

Activation of Molecular Oxygen Using Durable Cobalt Encapsulated with Nitrogen‐Doped Graphitic Carbon Shells for Aerobic Oxidation of Lignin‐Derived Alcohols

Nanostructured catalysts for electrochemical water splitting: current state and prospects

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