Simple Photoreduction of Graphene Oxide Nanosheet under Mild Conditions

Matsumoto, Yasumichi; Koinuma, Michio; Kim, Su Yeon; Watanabe, Yusuke; Taniguchi, Takaaki; Hatakeyama, Kazuto; Tateishi, Hikaru; Ida, Shintaro

doi:10.1021/am100900q

Cited by 218 publications

(165 citation statements)

References 56 publications

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“…1a). The rGO photoproduct can be distinguished from the GO spectrum by an increase of absorption in the 280-800 nm range that corresponds to the restoration of the p network of the carbon structure 25 . Figure 1c displays the Raman spectra from before (red) and after (black) ultraviolet irradiation.…”

Section: Resultsmentioning

confidence: 99%

“…Although each of these methods has its own merits, light-induced reduction of GO promises to be a rapid and facile way of producing rGO while avoiding the use of harsh chemicals. Pioneering work 21,[24][25][26][27] on the photoreduction deduced a reaction time scale that ranged from 600 ms 23 up to hours 26 . This literature provides a variety of recipes with a broad range of wavelengths, exposure times, light intensities and environments (solids and liquids).…”

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Revealing the ultrafast process behind the photoreduction of graphene oxide

et al. 2013

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Effective techniques to reduce graphene oxide are in demand owing to the multitude of potential applications of this two-dimensional material. A very promising green method to do so is by exposure to ultraviolet irradiation. Unfortunately, the dynamics behind this reduction remain unclear. Here we perform a series of transient absorption experiments in an effort to develop and understand this process on a fundamental level. An ultrafast photoinduced chain reaction is observed to be responsible for the graphene oxide reduction. The reaction is initiated using a femtosecond ultraviolet pulse that photoionizes the solvent, liberating solvated electrons, which trigger the reduction. The present study reaches the fundamental time scale of the ultraviolet photoreduction in solution, which is revealed to be in the picosecond regime.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Revealing the ultrafast process behind the photoreduction of graphene oxide

et al. 2013

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“…The photochemical reduction of GO was studied altering the wavelength, exposure time or light intensity, both in solids or in the liquid phase. [11][12][13][14][15] Although these great efforts have been undertaken the key-questions of understanding the dynamics and details of the reduction mechanism remain largely unanswered yet. In the present contribution we want to shed light on the issue of how GO is photo-reduced, what the reducing species is, and what the role of the solvated electron in this process is.…”

Section: Introductionmentioning

confidence: 99%

How fast is the reaction of hydrated electrons with graphene oxide in aqueous dispersions?

et al. 2015

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“…The binding energy of the epoxide COC peaks (287.2 eV) has been previously reported. 3,8,21 The deconvolution consisted of the sp 2 C=C (284.6 eV), CH (285.0 eV), sp 3 CC (285.5 eV), COH (286.4 eV), COC (287.2 eV), C=O (287.7 eV), and O=CO (288.8 eV) peaks. The deconvolution using the three peaks from non-oxygenated groups for diamond (sp 3 CC), HOPG (sp 2 C=C), and sodium dodecanedioate (CH) is critical to the analysis of rGO and rGtO.…”

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Analysis of Reduced Graphene Oxides by X-ray Photoelectron Spectroscopy and Electrochemical Capacitance

et al. 2013

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Reduced graphene oxide (rGO) and reduced graphite oxide (rGtO) were analyzed by X-ray photoelectron spectroscopy. rGO and rGtO were prepared by photochemical, electrochemical, hydrazine-assisted, and thermal reduction of graphene oxide (GO) and graphite oxide (GtO). The number of CH defects increased for the photochemical and electrochemical reduction, whereas a direct increase in the number of C=C bonds was observed for thermal and hydrazine-assisted reduction. Cyclic voltammograms showed that the electrochemical capacitance of rGtO increased with the number of CH defects.Reduced graphene oxide (rGO) has several advantages over graphene oxide (GO) for use in electrical devices. Typically, rGO is prepared by the thermal, 14 hydrazine-assisted, 47 or photochemical 810 reduction of GO. These treatments produce similar increases in the electrical conductivity, and the increase depends on the treatment conditions. Compositional differences have also been observed; for example, N doping has been detected after hydrazine-assisted reduction. 47 However, a detailed analysis of the functional groups in rGOs prepared by various reduction methods, particularly of the non-oxygenated functional groups (sp 3 CC, sp 3 CH, and sp 2 C=C bonds), has never been performed.We analyzed GO and rGO by X-ray photoelectron spectroscopy (XPS) and deconvoluting the C1s binding energies of the functional groups. Analysis of the CH defects is very important because they are key functional groups in rGO supercapacitor electrodes. 11,12 In this study, we demonstrate the importance of the CH defects on the electrochemical capacitance and the dependence of the differences in the functional groups of the rGO samples, particularly the CH defects, on the reduction method.Two types of GO samples were prepared by different methods. The rGO sample was prepared by the conventional Hammers' method, 13 using 98% graphite powder (Wako Chemicals) as the starting material. The graphite oxide (GtO; multilayered GO) sample was prepared by the electrochemical oxidation of glassy carbon (GC; BAS) in 0.1 M Na 2 SO 4 (Wako Chemicals) at 2.0 V (vs. Ag/AgCl) for 30 min.11 The electrochemical reduction of GtO was performed at ¹1.1 V in 0.1 M Na 2 SO 4 for 30 min. Photochemical, thermal, and hydrazineassisted reduction were conducted on both samples. The photochemical reduction was carried out under a 500-W Hg lamp for 1 h in H 2 . The thermal reduction was carried out in Ar at 300°C for 30 min. For the hydrazine-assisted reduction, the samples were immersed in a 10 M aqueous hydrazine solution at 60°C for 6 h.The XPS measurements were carried out using a Thermo Scientific SigmaProbe and monochromatic Al K¡ radiation. The instrument work function was calibrated to give a binding energy (BE) of 83.95 eV for the Au4f 7/2 line for metallic gold. The spectrometer dispersion was adjusted to give a BE of 368.25 eV for metallic Ag3d 5/2 and 932.65 eV for metallic Cu2p 3/2 . The instrument base pressure was 1 © 10 ¹9 mbar. High-resolution spectra were collected with a pass...

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Simple Photoreduction of Graphene Oxide Nanosheet under Mild Conditions

Cited by 218 publications

References 56 publications

Revealing the ultrafast process behind the photoreduction of graphene oxide

Revealing the ultrafast process behind the photoreduction of graphene oxide

How fast is the reaction of hydrated electrons with graphene oxide in aqueous dispersions?

Analysis of Reduced Graphene Oxides by X-ray Photoelectron Spectroscopy and Electrochemical Capacitance

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