Probing the Catalytic Activity of Reduced Graphene Oxide Decorated with Au Nanoparticles Triggered by Visible Light

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Artigo
Date
2015
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Chemistry - A European Journal
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22
Authors
Wang J.
Trindade F.J.
De Aquino C.B.
Pieretti J.C.
Domingues S.H.
Ando R.A.
Camargo P.H.C.
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Abstract
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Hybrid materials in which reduced graphene oxide (rGO) is decorated with Au nanoparticles (rGO-Au NPs) were obtained by the in situ reduction of GO and AuCl<inf>4</inf><sup>-</sup><inf>(aq)</inf> by ascorbic acid. On laser excitation, rGO could be oxidized as a result of the surface plasmon resonance (SPR) excitation in the Au NPs, which generates activated O<inf>2</inf> through the transfer of SPR-excited hot electrons to O<inf>2</inf> molecules adsorbed from air. The SPR-mediated catalytic oxidation of p-aminothiophenol (PATP) to p,p′-dimercaptoazobenzene (DMAB) was then employed as a model reaction to probe the effect of rGO as a support for Au NPs on their SPR-mediated catalytic activities. The increased conversion of PATP to DMAB relative to individual Au NPs indicated that charge-transfer processes from rGO to Au took place and contributed to improved SPR-mediated activity. Since the transfer of electrons from Au to adsorbed O<inf>2</inf> molecules is the crucial step for PATP oxidation, in addition to the SPR-excited hot electrons of Au NPs, the transfer of electrons from rGO to Au contributed to increasing the electron density of Au above the Fermi level and thus the Au-to-O<inf>2</inf> charge-transfer process.
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Keywords
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Au nanoparticle , Charge transfer process , Mediated activities , Model reactions , P-aminothiophenol , Reduced graphene oxides , Reduced graphene oxides (RGO) , Situ reduction
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