One-step electrochemical synthesis of tunable nitrogen-doped graphene

Lou, Fengliu; Buan, Marthe Emelie Melandsø; Muthuswamy, Navaneethan; Walmsley, John C.; Rønning, Magnus; Chen, De

doi:10.1039/c5ta08038j

Cited by 78 publications

(50 citation statements)

References 54 publications

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“…All measured potentials were converted to potential versus reversible hydrogen electrode (RHE) according to the following equation, unless specified

E_{vs RHE} = E_{vs Ag/AgCl} + E_{⊘ Ag/AgCl} + 0.059 pH

where E vs RHE is the potential versus RHE, E vs Ag/AgCl is the potential versus Ag/AgCl and E øAg/AgCl is the potential of Ag/AgCl electrode respect to the standard hydrogen electrode. The Koutechy–Levich (K–L) equation was used to calculate the electron transfer number ( n ) per oxygen molecule in ORR process at the electrode

B = 0.2 n F C_{0} D_{0}^{2 / 3} v^{- 1 / 6}

1 / J = 1 / J_{normalL} + 1 / J_{normalK} = 1 / (B ω^{1 / 2}) + 1 / J_{normalK}

where J is the measured current density, J L is the diffusion limiting current density, J K is the kinetic limiting current density, ω is the rotating speed in rpm, F is the Faraday constant (96 485 C mol −1 ), D 0 is the diffusion coefficient of oxygen in 0.1 mol L −1 KOH (1.9 × 10 −5 cm 2 s −1 ), v is the kinetic viscosity (0.01 cm 2 s −1 ), and C 0 is the buck concentration of oxygen (1.2 × 10 −3 mol L −1 ).…”

Section: Methodsmentioning

confidence: 99%

Sustainable and Atomically Dispersed Iron Electrocatalysts Derived from Nitrogen‐ and Phosphorus‐Modified Woody Biomass for Efficient Oxygen Reduction

Liu

Gan

et al. 2018

Adv Materials Inter

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Development of low‐cost, efficient, and robust electrocatalysts to replace precious platinum catalysts for oxygen reduction reaction (ORR) is urgent to boost the applications of green energy devices such as fuel cells and metal–air batteries. Herein, a low‐cost, simple, and easy‐to‐scale method to develop sustainable and cost‐effective ORR carbocatalysts via impregnation followed by pyrolysis of different renewable woody biomass is reported. Aberration‐corrected high‐angle annular dark field scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray absorption near edge structure measurements show that the nitrogen‐ and phosphorus‐promoted atomically dispersed iron is mainly responsible for the high ORR activity. Moreover, by a mimic of the natural pine materials derived Fe‐based electrocatalyst, introducing external Fe precursor into the biomass can generate targeted well dispersed Fe complex catalysts, which is not very much dependent on the biomass types. The insights revealed here can shed new light on the development of sustainable and cost‐effective ORR carbocatalysts from biomass.

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“…All measured potentials were converted to potential versus reversible hydrogen electrode (RHE) according to the following equation, unless specified

E_{vs RHE} = E_{vs Ag/AgCl} + E_{⊘ Ag/AgCl} + 0.059 pH

B = 0.2 n F C_{0} D_{0}^{2 / 3} v^{- 1 / 6}

1 / J = 1 / J_{normalL} + 1 / J_{normalK} = 1 / (B ω^{1 / 2}) + 1 / J_{normalK}

Section: Methodsmentioning

confidence: 99%

Sustainable and Atomically Dispersed Iron Electrocatalysts Derived from Nitrogen‐ and Phosphorus‐Modified Woody Biomass for Efficient Oxygen Reduction

Liu

Gan

et al. 2018

Adv Materials Inter

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“…Electrochemical exfoliation (EE) is one of the important methods to synthesize functionalized graphene as it offers precise control over the degree of functionalization in addition to room temperature operation to ensue morphological invariance. For instance, Bruna et al synthesized graphene oxyfluoride by using electrochemical exfoliation of graphite in an aqueous solution of HF acid.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Exfoliation of Graphite to Fluorographene: An Effect of Degree of Functionalization on 2Br⁻/Br₂ Redox Reaction

et al. 2019

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In this work, we employed the electrochemical exfoliation (EE) to synthesize and tune the degree of functionalization in fluorinated graphene (FG) and studied its (degree of functionalization) effect on bromine redox reaction. The degree of functionalization was tuned by varying the concentration of the electrolyte. Physical characterization of as‐synthesized FG reveals that fluorine and oxygen content varies from 2.32 to 3.92 atomic % and from 10.46 to 21.16 atomic % respectively. The concentration of fluoride to hydroxide ion ratio should be at an optimum level in the electrolyte to get maximum degree of fluorination, which shows a sizeable effect on bromine redox reaction. The bromine redox reaction is more reversible on highly FG and less reversible on less FG and Oxygen functionalities has no effect on the reaction. The kinetic parameters such as rate constant (k) (varying from 1.45 x 10−3 to 52.43 x 10−3 mA/cm2) and exchange current density (io) (varying from 2.61 x 10−4 to 9.92 x 10−4 cm/s) suggest that nature and degree of functionalization play a vital role to improve the kinetics of redox reaction of bromine. This investigation can pave paths to design new and sustainable electrode materials for bromine‐based redox flow batteries.

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“…Infrared spectroscopy was a very powerful tool for the detection of carbon based groups. Compared with pristine CC and Ar‐CC, the fourier transform infrared spectrum (FTIR) of OM‐CC showed an additional absorption around 1600 and 1800 cm −1 , which was associated with the vibration of COOH and C=O groups (Figure C) . It confirmed that oxygen functionalized sites was formed on the surface of carbon cloth with microwave treatment in air.…”

Section: Resultsmentioning

confidence: 82%

Microwave Reaction: A Facile Economic and Green Method to Synthesize Oxygen‐Decorated Graphene from Carbon Cloth for Oxygen Electrocatalysis

Zhang

et al. 2018

ChemCatChem

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Oxygen‐functionalized graphene is active for oxygen evolution reaction (OER). However, the high costs, complex instruments and pollution risks in the synthesis process make oxygen‐functionalized graphene difficult to be industrialized. The microwave reaction has originally been used to remove the oxygen groups on graphene structures. In this work, the microwave reaction is reversed to decorate oxygen groups on graphene from carbon cloth, by solely using a household microwave oven. After microwave treatment, the carbon cloth shows greatly improved OER performance with a much lower overpotential of 417 mV, in comparison with the pristine carbon cloth (627 mV), due to the decoration of oxygen groups on graphene, a higher electron conductivity and a higher specific surface area. Meanwhile, an overpotential of 542 mV at 10 mA cm−2 is obtained in an acidic electrolyte, which is one of the best values for non‐precious OER catalysts in acidic media. This work provides a facile, green and economic method for producing functionalized carbon catalysts for OER.

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One-step electrochemical synthesis of tunable nitrogen-doped graphene

Abstract: Nitrogen-doped graphene is synthesized by one-step electrochemical exfoliation of graphite, which exhibits superior catalytic performances towards the oxygen reduction reaction.

Cited by 78 publications

References 54 publications

Sustainable and Atomically Dispersed Iron Electrocatalysts Derived from Nitrogen‐ and Phosphorus‐Modified Woody Biomass for Efficient Oxygen Reduction

Sustainable and Atomically Dispersed Iron Electrocatalysts Derived from Nitrogen‐ and Phosphorus‐Modified Woody Biomass for Efficient Oxygen Reduction

Electrochemical Exfoliation of Graphite to Fluorographene: An Effect of Degree of Functionalization on 2Br⁻/Br₂ Redox Reaction

Microwave Reaction: A Facile Economic and Green Method to Synthesize Oxygen‐Decorated Graphene from Carbon Cloth for Oxygen Electrocatalysis

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One-step electrochemical synthesis of tunable nitrogen-doped graphene

Abstract: Nitrogen-doped graphene is synthesized by one-step electrochemical exfoliation of graphite, which exhibits superior catalytic performances towards the oxygen reduction reaction.

Cited by 78 publications

References 54 publications

Sustainable and Atomically Dispersed Iron Electrocatalysts Derived from Nitrogen‐ and Phosphorus‐Modified Woody Biomass for Efficient Oxygen Reduction

Sustainable and Atomically Dispersed Iron Electrocatalysts Derived from Nitrogen‐ and Phosphorus‐Modified Woody Biomass for Efficient Oxygen Reduction

Electrochemical Exfoliation of Graphite to Fluorographene: An Effect of Degree of Functionalization on 2Br−/Br2 Redox Reaction

Microwave Reaction: A Facile Economic and Green Method to Synthesize Oxygen‐Decorated Graphene from Carbon Cloth for Oxygen Electrocatalysis

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Electrochemical Exfoliation of Graphite to Fluorographene: An Effect of Degree of Functionalization on 2Br⁻/Br₂ Redox Reaction