This work was supported by the National Research Foundation of Korea (2013R1A1A1061387) and KU-KIST research fund.

1. Preparation of Precursor
<ol>
	<li>Preparation of graphene oxide (GO):
	<ol>
		<li>GO preparation using modified Hummer&#8217;s method14
		<ol>
			<li>Add 3.0 g of graphite flakes to a mixture of concentrated H2SO4/H3PO4 (360:40 ml) at RT. (Note: Special care has to be taken while using strong acids H2SO4 and H3PO4.)</li>
			<li>Add KMnO4 (18.0 g) slowly with stirring and cooling in an ice bath to maintain t...

<ol>
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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+Graphene+and+Its+Applications+A+Review.">Synthesis of Graphene and Its Applications A Review.</a> Crit Rev Solid State Mater Sci. 35 (1), 52-71 (2010).</li><li>Zhou, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microstructuring+of+Graphene+Oxide+Nanosheets+Using+Direct+Laser+Writing.">Microstructuring of Graphene Oxide Nanosheets Using Direct Laser Writing.</a> Adv Mater. 22 (1), 67-71 (2010).</li><li>Stankovich, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Graphene+Based+Composite+Materials.">Graphene Based Composite Materials.</a> Nature. 442 (7100), 282-286 (2006).</li><li>Becerril, H. 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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+Methods+for+the+Production+of+Graphenes.">Chemical Methods for the Production of Graphenes.</a> Nat Nanotechnol. 4 (4), 217-224 (2009).</li><li>Akhavan, O., Ghaderi, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photocatalytic+Reduction+of+Graphene+Oxide+Nanosheets+on+TiO2+Thin+Film+for+Photoinactivation+of+Bacteria+in+Solar+Light+Irradiation.">Photocatalytic Reduction of Graphene Oxide Nanosheets on TiO2 Thin Film for Photoinactivation of Bacteria in Solar Light Irradiation.</a> J Phys Chem C. 113 (47), 20214-20220 (2009).</li><li>Huang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsed+Laser+Assisted+Reduction+of+Graphene+Oxide.">Pulsed Laser Assisted Reduction of Graphene Oxide.</a> Carbon. 49 (7), 2431-2436 (2011).</li><li>Cote, L. J., Cruz-Silva, R., Huang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flash+Reduction+and+Patterning+of+Graphite+Oxide+and+Its+Polymer.">Flash Reduction and Patterning of Graphite Oxide and Its Polymer.</a> Composite. J. Am. Chem. Soc. 131 (31), 11027-11032 (2009).</li><li>Wu, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+plasmon+resonance-induced+visible+light+photocatalytic+reduction+of+graphene+oxide:+Using+Ag+nanoparticles+as+a+plasmonic+photocatalyst.">Surface plasmon resonance-induced visible light photocatalytic reduction of graphene oxide: Using Ag nanoparticles as a plasmonic photocatalyst.</a> Nanoscale. 3 (5), 2142-2144 (2011).</li><li>Kumar, D., Kaur, S., Lim, D. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmon-assisted+and+visible-light+induced+graphene+oxide+reduction+and+efficient+fluorescence+quenching.">Plasmon-assisted and visible-light induced graphene oxide reduction and efficient fluorescence quenching.</a> Chem. Commun. 50 (88), 13481-13484 (2014).</li><li>Gilje, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photothermal+Deoxygenation+of+Graphene+Oxide+for+Patterning+and+Distributed+Ignition+Applications.">Photothermal Deoxygenation of Graphene Oxide for Patterning and Distributed Ignition Applications.</a> Adv. Mater. 22 (3), 419-423 (2010).</li><li>Cote, L. J., Kim, F., Huang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Langmuir&#8722;Blodgett+Assembly+of+Graphite+Oxide+Single+Layers.">Langmuir&#8722;Blodgett Assembly of Graphite Oxide Single Layers.</a> J. Am. Chem. Soc. 131 (3), 1043-1049 (2008).</li><li>Ming, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Evidence+of+Plasmophores:+Plasmon-Directed+Polarized+Emission+from+Gold+Nanorod&#8211;Fluorophore+Hybrid+Nanostructures.">Experimental Evidence of Plasmophores: Plasmon-Directed Polarized Emission from Gold Nanorod&#8211;Fluorophore Hybrid Nanostructures.</a> Nano Lett. 11 (6), 2296-2303 (2011).</li><li>Xie, J., Lee, J. Y., Seedless Wang, D. I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactantless,+High-Yield+Synthesis+of+Branched+Gold+Nanocrystals+in+HEPES+Buffer+Solution.">Surfactantless, High-Yield Synthesis of Branched Gold Nanocrystals in HEPES Buffer Solution.</a> Chem. Mater. 19 (11), 2823-2830 (2007).</li><li>Ferrari, A. C., Robertson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resonant+Raman+spectroscopy+of+disordered,+amorphous,+and+diamond+like+carbon.">Resonant Raman spectroscopy of disordered, amorphous, and diamond like carbon.</a> Phys. Rev. B. 64 (7), 075414-1-075414-13 (2000).</li><li>Tian, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One&#8211;pot+green+hydrothermal+synthesis+of+CuO&#8211;Cu2O&#8211;Cu+nanorod&#8211;decorated+reduced+graphene+oxide+composites+and+their+application+in+photocurrent+generation.">One&#8211;pot green hydrothermal synthesis of CuO&#8211;Cu2O&#8211;Cu nanorod&#8211;decorated reduced graphene oxide composites and their application in photocurrent generation.</a> Catal. Sci. Technol. 2 (11), 2227-2230 (2012).</li><li>Liu, S., Tian, J., Wang, L., Sun, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+the+production+of+reduced+graphene+oxide+using+benzylamine+as+a+reducing+and+stabilizing+agent+and+its+subsequent+decoration+with+Ag+nanoparticles+for+enzymeless+hydrogen+peroxide+detection.">A method for the production of reduced graphene oxide using benzylamine as a reducing and stabilizing agent and its subsequent decoration with Ag nanoparticles for enzymeless hydrogen peroxide detection.</a> CARBON. 49 (10), 3158-3164 (2011).</li><li>Tian, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmentally+Friendly,+One&#8211;Pot+Synthesis+of+Ag+Nanoparticle+Decorated+Reduced+Graphene+Oxide+Composites+and+Their+Application+to+Photocurrent+Generation.">Environmentally Friendly, One&#8211;Pot Synthesis of Ag Nanoparticle Decorated Reduced Graphene Oxide Composites and Their Application to Photocurrent Generation.</a> Inorg. Chem. 51 (8), 4742-4746 (2012).</li><li>Tian, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three&#8211;Dimensional+Porous+Supramolecular+Architecture+from+Ultrathin+gC3N4+Nanosheets+and+Reduced+Graphene+Oxide:+Solution+Self-Assembly+Construction+and+Application+as+a+Highly+Efficient+Metal&#8211;Free+Electrocatalyst+for+Oxygen+Reduction+Reaction.">Three&#8211;Dimensional Porous Supramolecular Architecture from Ultrathin gC3N4 Nanosheets and Reduced Graphene Oxide: Solution Self-Assembly Construction and Application as a Highly Efficient Metal&#8211;Free Electrocatalyst for Oxygen Reduction Reaction.</a> ACS Appl. Mater. Interfaces. 6 (2), 1011-1017 (2014).</li><li>Liu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+Aqueous+Dispersion+of+Graphene+Nanosheets:+Noncovalent+Functionalization+by+a+Polymeric+Reducing+Agent+and+Their+Subsequent+Decoration+with+Ag+Nanoparticles+for+Enzymeless+Hydrogen+Peroxide+Detection.">Stable Aqueous Dispersion of Graphene Nanosheets: Noncovalent Functionalization by a Polymeric Reducing Agent and Their Subsequent Decoration with Ag Nanoparticles for Enzymeless Hydrogen Peroxide Detection.</a> Macromolecules. 43 (23), 10078-10083 (2010).</li><li>Li, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photocatalytic+synthesis+of+highly+dispersed+Pd+nanoparticles+on+reduced+graphene+oxide+and+their+application+in+methanol+electro&#8211;oxidation.">Photocatalytic synthesis of highly dispersed Pd nanoparticles on reduced graphene oxide and their application in methanol electro&#8211;oxidation.</a> Catal. Sci. Technol. 2 (6), 1153-1156 (2012).</li></ol>

We have nothing to disclose.

Visible light irradiation onto GO solution for 30 min with gold nanoparticles (AuNPs, AuNSs &#38; AuNRs) showed the rapid color changes from light yellow-brown to black color (Figure 1). To obtain highly pure r-GO product in high yield, there are two important factors need to follow. One is the use of AuNPs as an efficient plasmonic catalyst, since AuNPs can strongly absorb the visible light among other structures (i.e., AuNRs, AuNSs). Another is the use of nanosized GO solution to obtain nanopa...

The first developed scotch-tape based method1 and chemical vapor deposition2 were excellent methods to produce the pristine state of a graphene, but the large scale graphene synthesis or graphene layer formation on the surface with wide area have been regarded as a key limitation of previous methods.3 One of possible solution for large scale r-GO synthesis will be wet-chemical synthetic method which first requires the reactions with strong oxidants, extensive physical treatment such as sonication to produce GO sheet, and finally the reduction of oxygen functionalities such as hydroxy, epoxide and carbonyl groups in GO is essential in order to recover its original physical properties.4 Mostly, the reduction of GO was carried out with either chemical method using hydrazine or its derivatives5 or by thermal treatment method (550&#8211;1,100 &#176;C) in an inert or reducing atmosphere.6
These processes require the toxic chemicals, long reaction time and high temperature which increased total energy demand for r-GO synthesis.7 While the photo-irradiating reduction processes such as UV-induced,8 photo-thermal process using a pulsed xenon flash,9 pulsed laser assisted10 and photo-thermal heating with camera flash lights11 have also been reported for the preparation of r-GO. In general, the low conversion efficiency of the photo-induced methods propagated to the use of UV or pulsed laser irradiation that can deliver high photon energy. The low photon energy of visible light limits its use and not attracted much for r-GO synthesis. Excellent light absorption properties of plasmonic nanoparticles in the visible and/or NIR regions can greatly improve the current drawbacks of the use of visible light for r-GO synthesis.12,13 Mild reaction conditions, short reaction time and limited use of toxic chemicals could make the visible light induced plasmon assisted photocatalytic reduction of GO as a useful alternative method.
In present method, we describe the efficient and simple r-GO synthetic method using plasmonic nanoparticles and visible light. The reaction progress was found to be strongly dependent on the structures of plasmonic nanoparticles such as spherical gold nanoparticles (AuNPs), gold nanorods (AuNRs), and gold nanostars (AuNSs). The use of AuNPs showed the most efficient reduction of GO and the nanoparticles are easily removable and recyclable for the repeated use (Figure 1). The r-GO synthesized using visible light and AuNPs showed almost equal quality compared with the r-GO prepared by well-known chemical method (hydrazine) as demonstrated by use of various analytical measurements and the fluorescence quenching/recovery based DNA detection method.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Cy3 modifeid ssDNA</td>
			<td>IDT(Iowa, USA)</td>
			<td></td>
			<td>HPLC purified by IDT</td>
		</tr>
		<tr>
			<td>Gold nanoparticles (30 nm)</td>
			<td>Ted Pella, Inc(Redding, CA, USA).</td>
			<td>15706-20</td>
			<td>colloidal solution</td>
		</tr>
		<tr>
			<td>4-(2-hydroxyethyl)-1-piperazineethane sulfonic acid (HEPES) (99.5%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7365-45-9</td>
			<td></td>
		</tr>
		<tr>
			<td>Gold(III)Chloride Hydrate (99.999%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>&#160;27988-77-8</td>
			<td>strongly hygroscopic</td>
		</tr>
		<tr>
			<td>Sodium Borohydride (99.99%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>16940-66-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Hexadecyltrimethylammonium bromide (&#8805;99%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>57-09-0</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Ascorbic Acid(&#8805;99.0%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>50-81-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride (99.5%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Silver Nitrate&#160; (&#8805;99.0%)</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7761-88-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Graphite</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7782-42-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Sulfuric acid</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7664-93-9</td>
			<td></td>
		</tr>
		<tr>
			<td>Phophoric acid</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7664-38-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium permanganate</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>7722-64-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen peroxide</td>
			<td>JUNSEI</td>
			<td>23150-0350</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium hydroxide</td>
			<td>Sigma-Aldrich (St. Louis, MO, USA)</td>
			<td>1336-21-6</td>
			<td></td>
		</tr>
		<tr>
			<td>Xe-lamp</td>
			<td>&#160;Cermax, Waltham, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NIR Laser</td>
			<td>Class-IV, Sanctity Laser, Shanghai, China&#160;</td>
			<td></td>
			<td>6W (output power)</td>
		</tr>
		<tr>
			<td>UV-Vis spectrophotometer&#160;</td>
			<td>S-3100, SINCO, South Korea</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Transmission Electron Microscopy</td>
			<td>H-7650, Hitachi, Japan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Spectro Fluorometer</td>
			<td>Jasco FP-6500, Tokyo, Japan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>X-ray Photoelectron Spectrometer</td>
			<td>AXIS&#8211;NOVA, KRATOS Inc., UK</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

visible-light induced reduction of graphene oxide using plasmonic nanoparticle

Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using visible light irradiation with plasmonic nanoparticles. The plasmonic nanoparticle is used to improve the reduction efficiency of GO. It only takes 30 min&#160;at RT by illuminating the solutions with Xe-lamp, the r-GO solutions can be obtained by completely removing gold nanoparticles through simple centrifugation step. The spherical gold nanoparticles (AuNPs) as compared to the other nanostructures is the most suitable plasmonic nanostructure for r-GO preparation. The reduced graphene oxide prepared using visible light and AuNPs was equally qualitative as chemically reduced graphene oxide, which was supported by various analytical techniques such as UV-Vis spectroscopy, Raman spectroscopy, powder XRD and XPS. The reduced graphene oxide prepared with visible light shows excellent quenching properties over the fluorescent molecules modified on ssDNA and excellent fluorescence recovery for target DNA detection. The r-GO prepared by recycled AuNPs is found to be of same quality with that of chemically reduced r-GO. The use of visible light with plasmonic nanoparticle demonstrates the good alternative method for r-GO synthesis.

Figure 1 shows the overall scheme for visible light and plasmonic nanoparticle based r-GO reduction reaction. Figure 2 shows the instrumental setup for the reactions. After reaction, it is required the centrifugation step to remove the used photocatalyst (AuNSs, AuNRs, or AuNPs) as shown in Figure 3A. The HRTEM analysis shows the complete removal of nanoparticles in the supernatant (r-GO) (Figure 3B), which is also possible to confirm with UV-Visible ana...

Watch this Scientific Journal Video about Visible-light Induced Reduction of Graphene Oxide Using Plasmonic Nanoparticle at JoVE.com

Visible-light Induced Reduction of Graphene Oxide Using Plasmonic Nanoparticle

A simple protocol for the preparation of reduced graphene oxide using visible light and plasmonic nanoparticle is described.

Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using ...

visible-light-induced-reduction-graphene-oxide-using-plasmonic

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14.3K visualizações.  Korea University.  Um protocolo simples para a preparação de óxido de grafeno reduzido utilizando luz visível e nanopartículas plasmonic é descrito. 