Manipulation of defect density and nitrogen doping on few-layer graphene sheets using the plasma methodology for electrochemical applications

Chi, Yu-Wen; Hu, Chi‐Chang; Huang, Kun-Ping; Shen, Hsiao-Hsuan; Rajkumar, Muniyandi

doi:10.1016/j.electacta.2016.10.093

Cited by 16 publications

(7 citation statements)

References 46 publications

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“…In addition, direct plasma etching in nitrogen atmosphere is also one of the ways to obtain carbon‐based materials with pyridine nitrogen as the main nitrogen species. Chi [ 49 ] utilized 400–1600 W microwaves to motivate N plasma under the N 2 gas flow of 50 mL min −1 , making it possible for nitrogen atoms to be etched directly onto graphene sheets. The ratio of pyridine nitrogen in this material is as high as 68%.…”

Section: Nitrogen‐doping Experimental Methodsmentioning

confidence: 99%

H₂O₂ Electrogeneration from O₂ Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

Ding

Zhou

Gao

et al. 2021

Adv Materials Inter

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promising and environmentally friendly oxidant in advanced oxidation processes (AOPs). Besides, hydrogen peroxide received great attention in fuel cell as well, in which hydrogen still plays an important role. But the low volumetric energy density makes the storage of hydrogen a difficult issue. H 2 O 2 possesses a high energy density and oxidation potential [13] in full pH range (E 0 = 1.763 V at pH = 0, E 0 = 0.878 V at pH 14), [1] which enables it an ideal energy carrier alternative. [11] With a compounded increase of 6%, [14] the annual production of H 2 O 2 had reached 5.5 million tons in 2015. [1] At present, three main categories were conducted to produce H 2 O 2 : direct H 2 O 2 synthesis from H 2 and O 2 , [15] anthraquinone oxidation process (AO-process), [12] and oxygen electroreduction. [16][17] More than 95% of H 2 O 2 were synthesized by AO-process, involving hydrogenation and oxidation of the anthraquinone molecule over Ni or Pd catalysts in organic solvents. [14] However, AO-process is facing some challenges: 1) Low sustainability. The combustible and explosive substances used in AO-process, such as heavy aromatics, trioctyl phosphate, are not environmentally friendly, which brings a negative influence on the sustainability of the AO-process; 2) Transportation insecurity. The high concentration of H 2 O 2 has the potential to explode when flammable materials exist, which brings safety problems to transportation; 3) Exorbitant additional cost. Ahead of being transported, H 2 O 2 has to be concentrated up to 70 wt% with impurity separation [18] and requires acid promoter stabilizer, [14] causing the increase of extra cost. All these make AO-process not the best choice for low cost and distributed H 2 O 2 production.Comparatively, two-electron oxygen reduction reaction (ORR) provides an economic, efficient, and nonhazardous alternative process, achieving the in situ H 2 O 2 production under mild conditions. [1] Furthermore, ORR process could be coupled with renewable energy sources [18] and fuel cell, [19] recovering the energy released ( f 0 ∆G , 120 KJ mol −1 ). [20,21] For instance, solar energy can be directly used as an energy source to produce H 2 O 2 through photoelectric catalysis. [22] In brief, H 2 O 2 production via two-electron oxygen electro-reduction has emerged as a promising candidate to address the demand for distributed energy.Hydrogen peroxide (H 2 O 2 ) is one of the 100 most paramount chemicals in the world, which has been widely used in industrial synthesis, pulp and bleaching, semiconductor cleaning, medical sterilizing, environmental treatments, and energy storage. Among various H 2 O 2 production methods, anthraquinone process has intrinsic drawbacks such as energy-intensive and environmental pollution while 2-electron oxygen reduction reaction (ORR) provides an economic, efficient, and nonhazardous alternative process to realize the in situ production of H 2 O 2 instead. Recently, heteroatom-doped carbon electrocatalysts, especially the nitrogen-doped ones, receive special a...

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Section: Nitrogen‐doping Experimental Methodsmentioning

confidence: 99%

H₂O₂ Electrogeneration from O₂ Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

Ding

Zhou

Gao

et al. 2021

Adv Materials Inter

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“…Usually the graphitic, pyridinic, and other N content is determined with X-ray photoelectron spectroscopy, and the electrocatalytic effect is investigated depending on the different N content. On the basis of their results, several papers have suggested that the pyridinic N is the main contributor to the ORR activity, − while others suspect that the C atom’s neighboring graphitic N’s are the active center for the ORR. − According to a third standpoint, both types of N’s have their own role. Lai et al prepared two types of N-doped graphenes by annealing and found that graphitic N’s increase the limiting current density and that pyridinic N’s improve the onset potential.…”

Section: Introductionmentioning

confidence: 99%

Oxygen Reduction Reaction on N-Doped Graphene: Effect of Positions and Scaling Relations of Adsorption Energies

Ganyecz

Kállay

2021

J. Phys. Chem. C

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The goal of this study is to provide insight into the mechanism of the oxygen reduction reaction (ORR) on N-doped graphene surfaces. Using density functional theory and a computational hydrogen electrode model, we studied the energetics of the ORR intermediates, the effect of the position of the reaction site, and the effect of the position of the N modification relative to the active site on model graphene surfaces containing one or two N atoms. We found that scaling relations can be derived for N-doped graphenes as well, but the multiplicity of the surface should be taken into account. On the basis of the scaling relations between intermediates OOH* and OH*, the minimal overpotential is 0.33 V. Analysis of the data showed that N atoms in the meta position usually decrease the adsorption energy, but those in the ortho position aid the adsorption. The outer position on the zigzag edge of the graphene sheet also promotes the adsorption of oxygenated species, while the inner position hinders it. Looking at the most effective active sites, our analysis shows that the minimal overpotential can be approached with various doping arrangements, which also explains the contradicting results in the literature. The dissociative pathway was also investigated, but we found only one possible active site; therefore, this pathway is not really viable. However, routes not preferred thermodynamically pose the possibility of breaking the theoretical limit of the overpotential of the associative pathway.

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“…Ex situ plasma-assisted functionalisation and heteroatom doping of graphene provides the opportunity to modify and improve the properties of a wider variety of graphene materials which can been synthesised through the standard procedures, for example, micromechanical exfoliation, CVD, solution-based exfoliation, or chemical processing. Ex situ N-doping of graphene has been demonstrated by exposing micromechanically exfoliated graphene, highly oriented pyrolytic graphite, CVD graphene, and epitaxial graphene on SiC to various strengths of NH 3 [123][124][125], N 2 /H 2 [126][127][128], N 2 [129][130][131] and N 2 /O 3 [132] plasmas under low pressure conditions. Depending on the intensity and duration of processing conditions, the plasma modifications can be varied from mild N incorporation with pyridinic, pyrrolic and graphitic nitrogen and a preference for edge-functionalisation [124], to defect generation, and even significant etching which can subsequently yield N-doped graphene quantum nanosheets (figure 10(a)) [127].…”

Section: Graphenementioning

confidence: 99%

Recent progress in plasma-assisted synthesis and modification of 2D materials

et al. 2018

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Plasma represents an important technique for both the synthesis and modification of two-dimensional (2D) materials, owing to the unique plasma-material interactions which can enable effective energy transfer at the nanoscale. Non-equilibrium and non-thermal plasma techniques have been widely applied on various 2D materials, including graphene, silicene, germanene, phosphorene, hexagonal boron nitride (h-BN), and transition metal dichalcogenides such as MoS2 and WS2. Here, we review the recent progress in plasma-assisted synthesis and modification (e.g. functionalisation, doping and etching) of 2D materials and discuss the potential applications of this unique branch of 2D materials. Challenges and future research opportunities in the relevant research field are also discussed. The primary aim of this Review is to provide a better understanding of the plasma-assisted processes and to promote the utilization of 2D materials for advanced electronic, optoelectronic, sensing and energy storage applications.

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Manipulation of defect density and nitrogen doping on few-layer graphene sheets using the plasma methodology for electrochemical applications

Cited by 16 publications

References 46 publications

H₂O₂ Electrogeneration from O₂ Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

H₂O₂ Electrogeneration from O₂ Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

Oxygen Reduction Reaction on N-Doped Graphene: Effect of Positions and Scaling Relations of Adsorption Energies

Recent progress in plasma-assisted synthesis and modification of 2D materials

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Manipulation of defect density and nitrogen doping on few-layer graphene sheets using the plasma methodology for electrochemical applications

Cited by 16 publications

References 46 publications

H2O2 Electrogeneration from O2 Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

H2O2 Electrogeneration from O2 Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

Oxygen Reduction Reaction on N-Doped Graphene: Effect of Positions and Scaling Relations of Adsorption Energies

Recent progress in plasma-assisted synthesis and modification of 2D materials

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H₂O₂ Electrogeneration from O₂ Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects

H₂O₂ Electrogeneration from O₂ Electroreduction by N‐Doped Carbon Materials: A Mini‐Review on Preparation Methods, Selectivity of N Sites, and Prospects