Co4N/nitrogen-doped graphene: A non-noble metal oxygen reduction electrocatalyst for alkaline fuel cells

Varga, Tamás; Ballai, Gergő; Vásárhelyi, Lívia; Haspel, Henrik; Kukovecz, Ákos; Kónya, Zoltán

doi:10.1016/j.apcatb.2018.06.054

Cited by 87 publications

(30 citation statements)

References 72 publications

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“…25. There are two peaks located at 682 and 520 cm −1 for our pristine PW-Co 3 N NWA/NF, which is consistent with previous reports 30,55,56 . When the applied potential increased till 0.8 V vs. RHE, the peaks of PW-Co 3 N NWA/NF remained constant, which implied that there was no visible surface change during the HzOR process within the measured potential range.…”

Section: Discussionsupporting

confidence: 93%

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

et al. 2020

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Replacing sluggish oxygen evolution reaction (OER) with hydrazine oxidation reaction (HzOR) to produce hydrogen has been considered as a more energy-efficient strategy than water splitting. However, the relatively high cell voltage in two-electrode system and the required external electric power hinder its scalable applications, especially in mobile devices. Herein, we report a bifunctional P, W co-doped Co 3 N nanowire array electrode with remarkable catalytic activity towards both HzOR (−55 mV at 10 mA cm −2) and hydrogen evolution reaction (HER, −41 mV at 10 mA cm −2). Inspiringly, a record low cell voltage of 28 mV is required to achieve 10 mA cm −2 in two-electrode system. DFT calculations decipher that the doping optimized H* adsorption/desorption and dehydrogenation kinetics could be the underlying mechanism. Importantly, a self-powered H 2 production system by integrating a direct hydrazine fuel cell with a hydrazine splitting electrolyzer can achieve a decent rate of 1.25 mmol h −1 at room temperature.

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Section: Discussionsupporting

confidence: 93%

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

et al. 2020

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“…Two peaks at approximately 1342.0 and 1585.0 cm −1 , representing the defects and disordered carbon (D-band) and sp 2 graphitic carbon (G-band), respectively, can be observed in Co@CoSA/N-CNT/CC and Co 4 N@CoSA/N-CNT/CC. Three additional weak Raman peaks are detected at 468.4, 509.7, and 672.9 cm −1 in Co 4 N/CC and Co 4 N@CoSA/N-CNT/CC, which can be attributed to the meaningful contribution of the cobalt nitride phase 23 . Interestingly, the intensities of the D band to G band (I D / I G ) of Co 4 N@CoSA/N-CNT/CC are calculated to be 1.11, which is higher than the value of 0.96 for Co@CoSA/N-CNT/CC.…”

Section: Resultsmentioning

confidence: 94%

Tailoring the d-band center of N-doped carbon nanotube arrays with Co4N nanoparticles and single-atom Co for a superior hydrogen evolution reaction

et al. 2021

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A 3D self-supported integrated electrode, consisting of heteroatomic nitrogen-doped carbon nanotube arrays on carbon cloth with confined ultrafine Co4N nanoparticles and a distribution of anchored single-atom Co, is fabricated via a cobalt-catalyzed growth strategy using dicyandiamide as the nitrogen and carbon source and a layered cobalt hydroxide-nitrate salt as the precursor. The abundance of exposed active sites, namely, the Co4N nanoparticles, single-atom Co, and heteroatomic N-doped carbon nanotubes, and multiple synergistic effects among these components provide suitable tailoring of the d-band center for facilitating vectorial electron transfer and efficient electrocatalysis. Benefiting from the merits of its structural features and electronic configuration, the prepared electrode exhibits robust performance toward the hydrogen evolution reaction with overpotentials of only 78 and 86 mV at 10 mA cm−2 in acidic and basic electrolytes, respectively. Density functional theory calculations and X-ray photoelectron spectroscopy valence band measurements reveal that the effective tailoring of the d-band center by Co4N nanoparticles plays a crucial role in optimizing the hydrogen adsorption free energy to a more thermoneutral value for efficient electrocatalysis.

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“…This speculation was supported by the XPS result of the post‐used Pd/Co 3 N‐Ni 3 N/CFC catalyst. It was found that the O 1s spectra of the spent catalyst can be deconvoluted well into three characteristic peaks at 530.7, 531.8, and 533.4 eV, which correspond to the nickel/cobalt oxides, carboxyls, and hydroxys, respectively (Figure S3, Supporting Information) 55–57. In addition, CO stripping experiments further provided evidence supporting the promoting effect of synergistic phases in oxidative removal of carbonaceous intermediates.…”

Section: Resultsmentioning

confidence: 75%

Hierarchical Nanostructured Pd/Co₃N‐Ni₃N as an Efficient Catalyst for Ethanol Electrooxidation in Alkaline Media

Tang

Gao

et al. 2020

Adv Materials Inter

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to synthesize multicomponent and/or nanocomposite catalysts. Alloying Pt or Pd with 3d transition metals provides a straightforward way to alter the electronic structure and optimize the binding energies of adsorbates on the catalyst surface. [15][16][17][18][19][20][21][22][23][24][25] Creating synergistic catalysts via a combination of noble metals with oxophilic metal oxides/hydroxides proved a promising approach for improving the durability. [26][27][28][29][30][31][32][33][34] In a rational catalyst design, the OH adspecies on the surface of oxides/ hydroxides will facilitate the oxidative removal of carbonaceous intermediates adsorbed on the nearby Pd or Pt sites.Recently, the search for synergistic phases was further extended to transition metal non-oxides, like phosphides, [35][36][37][38] sulfides, [39] carbides, [40,41] and nitrides. [42][43][44][45][46] In comparison with the corresponding oxides, metal non-oxides exhibit much more abundant physicochemical properties owing to the complex and tunable interactions between metals and non-oxygen elements. For instance, in contrast to the insulator nature of most oxides, transition metal non-oxides span a remarkable range of conductivity properties, from insulator to semiconductor and to metal. Evidently, a rich variety of metal non-oxides with diverse properties offers increased degrees of freedom in the design of synergestic catalysts for the EOR. Among the materials of choice, transition metal nitrides (TMNs) are highly appealing but less well explored candidates. Theoretical studies found that TMNs (like Ni 3 N) typically show moderate binding energies of OH species, implying a compromise between the activation of OH and poisoning of the surface with reaction intermediates. [47] This, together with their high electrical conductivity and good chemical stability, clearly suggests the potential of TMN as a component phase in the synergistic catalysis of EOR. [48,49] Herein, we report the synthesis of a carbon fiber clothsupported nanocomposite catalyst consisting of highly dispersed Pd nanoparticles on the porous Co 3 N-Ni 3 N nanowires using a hydrothermal method followed by ammonization treatment and electrochemical deposition. Our study found that incorporation of Co 3 N-Ni 3 N of metallic nature could effectively improve the poisoning tolerance, while preserving good electrical conductivity of the electrocatalyst. Furthermore, the resulting hierarchical nanostructure of Co 3 N-Ni 3 N from the applied synthesis methods ensures the exposure of abundant active sites and a favorable reactant/product mass transfer kinetics. As a consequence, the Pd/Co 3 N-Ni 3 N/CFC catalyst Creating synergistic active sites via combination of palladium (Pd) or platinum (Pt) with oxophilic metal compounds has been extensively investigated as a promising approach for developing active and robust electrocatalysts toward the ethanol oxidation reaction (EOR). Among the metal compounds of choice, transition metal nitrides are highly appealing but less well explored candidates. H...

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Co4N/nitrogen-doped graphene: A non-noble metal oxygen reduction electrocatalyst for alkaline fuel cells

Cited by 87 publications

References 72 publications

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

Tailoring the d-band center of N-doped carbon nanotube arrays with Co4N nanoparticles and single-atom Co for a superior hydrogen evolution reaction

Hierarchical Nanostructured Pd/Co₃N‐Ni₃N as an Efficient Catalyst for Ethanol Electrooxidation in Alkaline Media

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Co4N/nitrogen-doped graphene: A non-noble metal oxygen reduction electrocatalyst for alkaline fuel cells

Cited by 87 publications

References 72 publications

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

Tailoring the d-band center of N-doped carbon nanotube arrays with Co4N nanoparticles and single-atom Co for a superior hydrogen evolution reaction

Hierarchical Nanostructured Pd/Co3N‐Ni3N as an Efficient Catalyst for Ethanol Electrooxidation in Alkaline Media

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Hierarchical Nanostructured Pd/Co₃N‐Ni₃N as an Efficient Catalyst for Ethanol Electrooxidation in Alkaline Media