title: Probing the Catalytic Activity of Reduced Graphene Oxide Decorated with Au Nanoparticles Triggered by Visible Light.
abstract: 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 AuCl4(-)(aq) 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 O2 through the transfer of SPR-excited hot electrons to O2 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 O2 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-O2 charge-transfer process.
authors.affiliation: Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes, 748, 05508-000 São Paulo, SP (Brazil).
authors.forename: Jiale
authors.initials: J
authors.lastname: Wang
authors.affiliation: Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes, 748, 05508-000 São Paulo, SP (Brazil).
authors.forename: Fabiane J
authors.initials: FJ
authors.lastname: Trindade
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, Rua da Consolação, 896, 01302-907 São Paulo, SP (Brazil).
authors.forename: Caroline B
authors.initials: CB
authors.lastname: de Aquino
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, Rua da Consolação, 896, 01302-907 São Paulo, SP (Brazil).
authors.forename: Joana C
authors.initials: JC
authors.lastname: Pieretti
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, Rua da Consolação, 896, 01302-907 São Paulo, SP (Brazil).
authors.forename: Sergio H
authors.initials: SH
authors.lastname: Domingues
authors.affiliation: Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes, 748, 05508-000 São Paulo, SP (Brazil).
authors.forename: Romulo A
authors.initials: RA
authors.lastname: Ando
authors.affiliation: Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes, 748, 05508-000 São Paulo, SP (Brazil). camargo@iq.usp.br.
authors.forename: Pedro H C
authors.initials: PH
authors.lastname: Camargo
keywords: gold; graphene; nanoparticles; photocatalysis; surface plasmon resonance