51
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Cristarella TC, Chinderle AJ, Hui J, Rodríguez-López J. Single-layer graphene as a stable and transparent electrode for nonaqueous radical annihilation electrogenerated chemiluminescence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3999-4007. [PMID: 25780938 DOI: 10.1021/la5050317] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We explored the use of single-layer graphene (SLG) obtained by chemical vapor deposition, and transferred to a glass substrate, as a transparent electrode material for use in coupled electrochemical and spectroscopic experiments in nonaqueous media through electrogenerated chemiluminescence (ECL). SLG was used with classical ECL luminophores, rubrene and 9,10-diphenylanthracene, in an inert environment to generate stable electrochemical responses and measure light emission through it. As an electrode material, SLG displayed excellent stability during electrochemical potential stepping and voltammetry in a window that spanned at least from ca. -2.4 to +1.8 V versus SCE in acetonitrile and acetonitrile/benzene. Although the peak splitting between forward and reverse sweeps in voltammetry was larger in comparison to metal electrodes due to in-plane resistance, SLG displayed sufficiently facile electron transfer properties to yield stable voltammetric cycling and ECL. SLG electrodes patterned with poly tetrafluoroethylene permitted the stable generation of radical ions on an SLG microelectrode to be studied through scanning electrochemical microscopy in the generation/collection mode. SLG was able to stably collect radical ions produced by a 50 μm gold tip with up to 96% collection efficiency. The transparency of graphene was used to obtain accurate spectral responses in ECL. While inner filter effects are known to cause a shift in peak emission wavelength of spectroelectrochemical studies, the use of SLG electrodes with detection through the graphene window reduced apparent peak shifts by up to 10 nm in peak wavelength. This work introduces SLG as a virtually transparent, electrochemically active, and chemically stable platform for studying ECL in the radical annihilation mode, where large electrode polarizations could compromise the chemical stability of other existing transparent electrodes.
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Affiliation(s)
- Teresa C Cristarella
- †Department of Chemistry and ‡Department of Material Sciences and Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Ave., Urbana, Illinois 61801, United States
| | - Adam J Chinderle
- †Department of Chemistry and ‡Department of Material Sciences and Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Ave., Urbana, Illinois 61801, United States
| | - Jingshu Hui
- †Department of Chemistry and ‡Department of Material Sciences and Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Ave., Urbana, Illinois 61801, United States
| | - Joaquín Rodríguez-López
- †Department of Chemistry and ‡Department of Material Sciences and Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Ave., Urbana, Illinois 61801, United States
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52
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Bosch-Navarro C, Laker ZPL, Rourke JP, Wilson NR. Reproducible, stable and fast electrochemical activity from easy to make graphene on copper electrodes. Phys Chem Chem Phys 2015; 17:29628-36. [DOI: 10.1039/c5cp04070a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chemical vapor deposition grown graphene on copper is a fast, robust and easy to make electrochemical electrode. The electrochemical response is independent of the amount of basal-plane/edge-plane of graphene, and fully covered samples show no electrode fouling, giving a simple route to study graphene based electrodes.
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53
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Brownson DAC, Kelly PJ, Banks CE. In situ electrochemical characterisation of graphene and various carbon-based electrode materials: an internal standard approach. RSC Adv 2015. [DOI: 10.1039/c5ra03049h] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An internal standard protocol is utilised to simultaneously characterise and utilise carbon-based electrode materials during their implementation.
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Affiliation(s)
- Dale A. C. Brownson
- Faculty of Science and Engineering
- School of Science and the Environment
- Division of Chemistry and Environmental Science
- Manchester Metropolitan University
- Manchester M1 5GD
| | - Peter J. Kelly
- Faculty of Science and Engineering
- School of Science and the Environment
- Division of Chemistry and Environmental Science
- Manchester Metropolitan University
- Manchester M1 5GD
| | - Craig E. Banks
- Faculty of Science and Engineering
- School of Science and the Environment
- Division of Chemistry and Environmental Science
- Manchester Metropolitan University
- Manchester M1 5GD
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54
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Zhang B, Yuan H, Zhang X, Huang D, Li S, Wang M, Shen Y. Investigation of regeneration kinetics in quantum-dots-sensitized solar cells with scanning electrochemical microscopy. ACS APPLIED MATERIALS & INTERFACES 2014; 6:20913-20918. [PMID: 25397869 DOI: 10.1021/am505569w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A fast quantum dots (QDs) regeneration process is necessary for highly efficient QDs-sensitized solar cells. Herein, CdSe and CdS QDs regeneration rates (kQD') in three redox electrolytes, which are triiodide and iodide ions (I3(-)/I(-)), Co(bpy)3(PF6)2 and Co(bpy)3(PF6)3 (Co(3+)/Co(2+)), and 1-methy-1-H-tetrazole-5-thiolate and its dimer (T2/T(-)), have been first investigated with scanning electrochemical microscopy (SECM). The results reveal that the kinetics of QDs regeneration depends on the nature of the QDs and the redox shuttles presented in QDSSCs. For QDs of CdSe and CdS, the regeneration rate (kQD') in the case of a T2/T(-)-based electrolyte is about two times larger than that of Co(3+)/Co(2+) and I3(-)/I(-). Additionally, the kQD' for CdSe is about two times larger than that of CdS in the same redox shuttle electrolyte, which could be due to a large driving force for the reaction between the exited state quantum dots (QD(+)) and redox electrolytes.
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Affiliation(s)
- Bingyan Zhang
- Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
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55
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Bourgeteau T, Le Vot S, Bertucchi M, Derycke V, Jousselme B, Campidelli S, Cornut R. New Insights into the Electronic Transport of Reduced Graphene Oxide Using Scanning Electrochemical Microscopy. J Phys Chem Lett 2014; 5:4162-4166. [PMID: 26278948 DOI: 10.1021/jz502224f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The present work investigates the electronic conduction of reduced graphene oxide flakes and the coupling between flakes through a combined SECM (scanning electrochemical microscopy), AFM, and SEM analysis. Images of individual and interconnected flakes directly reveal the signature of the contact resistance between flakes in a noncontact and substrate-independent way. Quantitative evaluation of the parameters is achieved with the support of numerical simulations to interpret the experimental results. The interflakes contact resistance importantly impacts the transport of electrons, which can be anticipated as a key parameter in r-GO-based materials used in fuel cells, lithium batteries, supercapacitors, and organic electronic devices.
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Affiliation(s)
- Tiphaine Bourgeteau
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
| | - Steven Le Vot
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
| | - Michael Bertucchi
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
| | - Vincent Derycke
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
| | - Bruno Jousselme
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
| | - Stéphane Campidelli
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
| | - Renaud Cornut
- CEA Saclay, IRAMIS, NIMBE, LICSEN, Bat. 466, Gif-sur-Yvette, Cedex F-91191, France
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56
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Zhong JH, Zhang J, Jin X, Liu JY, Li Q, Li MH, Cai W, Wu DY, Zhan D, Ren B. Quantitative Correlation between Defect Density and Heterogeneous Electron Transfer Rate of Single Layer Graphene. J Am Chem Soc 2014; 136:16609-17. [DOI: 10.1021/ja508965w] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Jin-Hui Zhong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Jie Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Xi Jin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Jun-Yang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Qiongyu Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Mao-Hua Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Weiwei Cai
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - De-Yin Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Dongping Zhan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
| | - Bin Ren
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, and ‡Department of Physics, Laboratory of Nanoscale Condensed Matter Physics, Xiamen University, Xiamen 361005, China
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57
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Velický M, Bradley DF, Cooper AJ, Hill EW, Kinloch IA, Mishchenko A, Novoselov KS, Patten HV, Toth PS, Valota AT, Worrall SD, Dryfe RAW. Electron transfer kinetics on mono- and multilayer graphene. ACS NANO 2014; 8:10089-10100. [PMID: 25290250 DOI: 10.1021/nn504298r] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding of the electrochemical properties of graphene, especially the electron transfer kinetics of a redox reaction between the graphene surface and a molecule, in comparison to graphite or other carbon-based materials, is essential for its potential in energy conversion and storage to be realized. Here we use voltammetric determination of the electron transfer rate for three redox mediators, ferricyanide, hexaammineruthenium, and hexachloroiridate (Fe(CN)(6)(3-), Ru(NH3)(6)(3+), and IrCl(6)(2-), respectively), to measure the reactivity of graphene samples prepared by mechanical exfoliation of natural graphite. Electron transfer rates are measured for varied number of graphene layers (1 to ca. 1000 layers) using microscopic droplets. The basal planes of mono- and multilayer graphene, supported on an insulating Si/SiO(2) substrate, exhibit significant electron transfer activity and changes in kinetics are observed for all three mediators. No significant trend in kinetics with flake thickness is discernible for each mediator; however, a large variation in kinetics is observed across the basal plane of the same flakes, indicating that local surface conditions affect the electrochemical performance. This is confirmed by in situ graphite exfoliation, which reveals significant deterioration of initially, near-reversible kinetics for Ru(NH3)(6)(3+) when comparing the atmosphere-aged and freshly exfoliated graphite surfaces.
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Affiliation(s)
- Matěj Velický
- School of Chemistry, §School of Computer Science, ∥School of Materials, ⊥School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
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58
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Stevenson KJ, Veneman PA, Gearba RI, Mueller KM, Holliday BJ, Ohta T, Chan CK. Controlled covalent modification of epitaxial single layer graphene on 6H-SiC (0001) with aryliodonium salts using electrochemical methods. Faraday Discuss 2014; 172:273-91. [DOI: 10.1039/c4fd00038b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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59
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Chen ZB, Peng ZL, Liang JH, Zhou XS, Wu DY, Amatore C, Mao BW. Gold atomic contact: Electron conduction in the presence of interfacial charge transfer. Electrochem commun 2014. [DOI: 10.1016/j.elecom.2014.07.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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60
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O'Neil GD, Weber AW, Buiculescu R, Chaniotakis NA, Kounaves SP. Electrochemistry of aqueous colloidal graphene oxide on Pt electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9599-9606. [PMID: 25019927 DOI: 10.1021/la502053m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The electrochemical behavior of colloidal solutions of graphene oxide (GO) is described here in detail. The GO reduction is shown to exhibit near-reversible electron transfer on Pt electrodes, based on E1/2 and ΔEp values. The observed peak current is found to depend linearly on the concentration of the GO and the square root of the scan rate, suggesting that the response is diffusion-limited. The difference between the experimental and diffusion-only limited theoretical current values suggests that migration may be hindering mass transport to the electrode surface. Varying the type and concentration of the supporting electrolyte showed that mass transport is weakly influenced by the presence of negative charges on the graphene particles. The effect of pH on GO was also investigated, and it was found that the reduction peak heights were directly related to proton concentration in acidic solutions. On the basis of the results presented here, we propose that the observed response of GO on Pt electrodes is a result of the reduction of protons from the colloidal double layer. This difference is observed only because the Pt electrode surface can efficiently catalyze proton reduction.
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Affiliation(s)
- Glen D O'Neil
- Department of Chemistry, Tufts University , Medford, Massachusetts 02155, United States
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61
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Ritzert NL, Li W, Tan C, Rodríguez-Calero GG, Rodríguez-López J, Hernández-Burgos K, Conte S, Parks JJ, Ralph DC, Abruña HD. Single layer graphene as an electrochemical platform. Faraday Discuss 2014; 172:27-45. [DOI: 10.1039/c4fd00060a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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62
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Zhang B, Xu X, Zhang X, Huang D, Li S, Zhang Y, Zhan F, Deng M, He Y, Chen W, Shen Y, Wang M. Investigation of Dye Regeneration Kinetics in Sensitized Solar Cells by Scanning Electrochemical Microscopy. Chemphyschem 2014; 15:1182-9. [DOI: 10.1002/cphc.201301076] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 02/17/2014] [Indexed: 11/06/2022]
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63
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Hernández-Ferrer J, Laporta P, Gutiérrez F, Rubianes MD, Rivas G, Martínez MT. Multi-walled carbon nanotubes/graphene nanoribbons hybrid materials with superior electrochemical performance. Electrochem commun 2014. [DOI: 10.1016/j.elecom.2013.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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64
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McCreery R, Bergren A, Morteza-Najarian A, Sayed SY, Yan H. Electron transport in all-carbon molecular electronic devices. Faraday Discuss 2014; 172:9-25. [DOI: 10.1039/c4fd00172a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Carbon has always been an important electrode material for electrochemical applications, and the relatively recent development of carbon nanotubes and graphene as electrodes has significantly increased interest in the field. Carbon solids, both sp2 and sp3 hybridized, are unique in their combination of electronic conductivity and the ability to form strong bonds to a variety of other elements and molecules. The Faraday Discussion included broad concepts and applications of carbon materials in electrochemistry, including analysis, energy storage, materials science, and solid-state electronics. This introductory paper describes some of the special properties of carbon materials useful in electrochemistry, with particular illustrations in the realm of molecular electronics. The strong bond between sp2 conducting carbon and aromatic organic molecules enables not only strong electronic interactions across the interface between the two materials, but also provides sufficient stability for practical applications. The last section of the paper discusses several factors which affect the electron transfer kinetics at highly ordered pyrolytic graphite, some of which are currently controversial. These issues bear on the general question of how the structure and electronic properties of the carbon electrode material control its utility in electrochemistry and electron transport, which are the core principles of electrochemistry using carbon electrodes.
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Affiliation(s)
- Richard McCreery
- Department of Chemistry
- University of Alberta
- Canada
- National Institute for Nanotechnology
- Edmonton, Canada
| | - Adam Bergren
- National Institute for Nanotechnology
- Edmonton, Canada
| | - Amin Morteza-Najarian
- Department of Chemistry
- University of Alberta
- Canada
- National Institute for Nanotechnology
- Edmonton, Canada
| | - Sayed Youssef Sayed
- Department of Chemistry
- University of Alberta
- Canada
- National Institute for Nanotechnology
- Edmonton, Canada
| | - Haijun Yan
- National Institute for Nanotechnology
- Edmonton, Canada
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65
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Toth PS, Valota AT, Velický M, Kinloch IA, Novoselov KS, Hill EW, Dryfe RAW. Electrochemistry in a drop: a study of the electrochemical behaviour of mechanically exfoliated graphene on photoresist coated silicon substrate. Chem Sci 2014. [DOI: 10.1039/c3sc52026a] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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66
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Chen S, Liu Y, Chen J. Heterogeneous electron transfer at nanoscopic electrodes: importance of electronic structures and electric double layers. Chem Soc Rev 2014; 43:5372-86. [DOI: 10.1039/c4cs00087k] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Recent insights into the nanoscopic electrode size and structure effects on heterogeneous ET kinetics are presented.
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Affiliation(s)
- Shengli Chen
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education)
- Hubei Key Laboratory of Electrochemical Power Sources
- Department of Chemistry
- Wuhan University
- Wuhan 430072, China
| | - Yuwen Liu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education)
- Hubei Key Laboratory of Electrochemical Power Sources
- Department of Chemistry
- Wuhan University
- Wuhan 430072, China
| | - Junxiang Chen
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education)
- Hubei Key Laboratory of Electrochemical Power Sources
- Department of Chemistry
- Wuhan University
- Wuhan 430072, China
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67
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Ribeiro S, Cunha-Silva L, Balula SS, Gago S. Cobalt(iii) sepulchrate complexes: application as sustainable oxidative catalysts. NEW J CHEM 2014. [DOI: 10.1039/c4nj00120f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The application of cobalt sepulchrate (sep) complexes as active and robust homogeneous catalysts is reported here for the first time, as well as the crystal structure of the [Co(sep)]2(SO4)3·10H2O compound.
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Affiliation(s)
- Susana Ribeiro
- REQUIMTE
- Departamento de Química e Bioquímica
- Faculdade de Ciências
- Universidade do Porto
- 4169-007 Porto, Portugal
| | - Luís Cunha-Silva
- REQUIMTE
- Departamento de Química e Bioquímica
- Faculdade de Ciências
- Universidade do Porto
- 4169-007 Porto, Portugal
| | - Salete S. Balula
- REQUIMTE
- Departamento de Química e Bioquímica
- Faculdade de Ciências
- Universidade do Porto
- 4169-007 Porto, Portugal
| | - Sandra Gago
- REQUIMTE
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Monte de Caparica, Portugal
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68
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Lounasvuori MM, Rosillo-Lopez M, Salzmann CG, Caruana DJ, Holt KB. Electrochemical characterisation of graphene nanoflakes with functionalised edges. Faraday Discuss 2014; 172:293-310. [DOI: 10.1039/c4fd00034j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Graphene nanoflakes (GNF) of diameter ca. 30 nm and edge-terminated with carboxylic acid (COOH) or amide functionalities were characterised electrochemically after drop-coating onto a boron-doped diamond (BDD) electrode. In the presence of the outer-sphere redox probe ferrocenemethanol there was no discernible difference in electrochemical response between the clean BDD and GNF-modified electrodes. When ferricyanide or hydroquinone were used as redox probes there was a marked difference in response at the electrode modified with COOH-terminated GNF in comparison to the unmodified BDD and amide-terminated GNF electrode. The response of the COOH-terminated GNF electrode was highly pH dependent, with the most dramatic differences in response noted at pH < 8. This pH range coincides with partial protonation of the carboxylic acid groups as determined by titration. The acid edge groups occupy a range of bonding environments and are observed to undergo deprotonation over a pH range ca. 3.7 to 8.3. The protonation state of the GNF influences the oxidation mechanism of hydroquinone and in particular the number of solution protons involved in the reaction mechanism. The voltammetric response of ferricyanide is very inhibited by the presence of COOH-terminated GNF at pH < 8, especially in low ionic strength solution. While the protonation state of the GNF is clearly a major factor in the observed response, the exact role of the acid group in the redox process has not been firmly established. It may be that the ferricyanide species is unstable in the solution environment surrounding the GNF, where dynamic protonation equilibria are at play, perhaps through disruption to ion pairing.
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Affiliation(s)
| | | | | | - Daren J. Caruana
- Department of Chemistry
- University College London
- London WC1H 0AJ, United Kingdom
| | - Katherine B. Holt
- Department of Chemistry
- University College London
- London WC1H 0AJ, United Kingdom
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69
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Kirkman PM, Güell AG, Cuharuc AS, Unwin PR. Spatial and Temporal Control of the Diazonium Modification of sp2 Carbon Surfaces. J Am Chem Soc 2013; 136:36-9. [DOI: 10.1021/ja410467e] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Paul M. Kirkman
- Department of Chemistry, University of Warwick, Gibbet Hill
Road, Coventry, CV4 7AL, U.K
| | - Aleix G. Güell
- Department of Chemistry, University of Warwick, Gibbet Hill
Road, Coventry, CV4 7AL, U.K
| | - Anatolii S. Cuharuc
- Department of Chemistry, University of Warwick, Gibbet Hill
Road, Coventry, CV4 7AL, U.K
| | - Patrick R. Unwin
- Department of Chemistry, University of Warwick, Gibbet Hill
Road, Coventry, CV4 7AL, U.K
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70
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Wei D, Kivioja J. Graphene for energy solutions and its industrialization. NANOSCALE 2013; 5:10108-10126. [PMID: 24057074 DOI: 10.1039/c3nr03312k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Graphene attracts intensive interest globally across academia and industry since the award of the Nobel Prize in Physics 2010. Within the last half decade, there has been an explosion in the number of scientific publications, patents and industry projects involved in this topic. On the other hand, energy is one of the biggest challenges of this century and related to the global sustainable economy. There are many reviews on graphene and its applications in various devices, however, few of the review articles connect the intrinsic properties of graphene with its energy. The IUPAC definition of graphene refers to a single carbon layer of graphite structure and its related superlative properties. A lot of scientific results on graphene published to date are actually dealing with multi-layer graphenes or reduced graphenes from insulating graphene oxides (GO) which contain defects and contaminants from the reactions and do not possess some of the intrinsic physical properties of pristine graphene. In this review, the focus is on the most recent advances in the study of pure graphene properties and novel energy solutions based on these properties. It also includes graphene metrology and analysis of both intellectual property and the value chain for the existing and forthcoming graphene industry that may cause a new 'industry revolution' with the strong and determined support of governments and industries across the European Union, U. S., Asia and many other countries in the world.
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Affiliation(s)
- Di Wei
- Nokia Research Center, Broers Building, 21 J. J. Thomson Avenue, Cambridge, CB3 0FA, UK.
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Song CK, White AC, Zeng L, Leever BJ, Clark MD, Emery JD, Lou SJ, Timalsina A, Chen LX, Bedzyk MJ, Marks TJ. Systematic investigation of organic photovoltaic cell charge injection/performance modulation by dipolar organosilane interfacial layers. ACS APPLIED MATERIALS & INTERFACES 2013; 5:9224-9240. [PMID: 23942417 DOI: 10.1021/am4030609] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
With the goal of investigating and enhancing anode performance in bulk-heterojunction (BHJ) organic photovoltaic (OPV) cells, the glass/tin-doped indium oxide (ITO) anodes are modified with a series of robust silane-tethered bis(fluoroaryl)amines to form self-assembled interfacial layers (IFLs). The modified ITO anodes are characterized by contact angle measurements, X-ray reflectivity, ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, grazing incidence X-ray diffraction, atomic force microscopy, and cyclic voltammetry. These techniques reveal the presence of hydrophobic amorphous monolayers of 6.68 to 9.76 Å thickness, and modified anode work functions ranging from 4.66 to 5.27 eV. Two series of glass/ITO/IFL/active layer/LiF/Al BHJ OPVs are fabricated with the active layer = poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester (P3HT:PC71BM) or poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)-carbonyl]thi-eno[3,4-b]thiophenediyl]]:phenyl-C71-butyric acid methyl ester (PTB7:PC71BM). OPV analysis under AM 1.5G conditions reveals significant performance enhancement versus unmodified glass/ITO anodes. Strong positive correlations between the electrochemically derived heterogeneous electron transport rate constants (ks) and the device open circuit voltage (Voc), short circuit current (Jsc), hence OPV power conversion efficiency (PCE), are observed for these modified anodes. Furthermore, the strong functional dependence of the device response on ks increases as greater densities of charge carriers are generated in the BHJ OPV active layer, and is attributable to enhanced anode carrier extraction in the case of high-ks IFLs.
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Affiliation(s)
- Charles Kiseok Song
- Department of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States
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Chakrabarti M, Low C, Brandon N, Yufit V, Hashim M, Irfan M, Akhtar J, Ruiz-Trejo E, Hussain M. Progress in the electrochemical modification of graphene-based materials and their applications. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.06.030] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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