| Texto completo | |
| Autor(es): |
Wang, Jiale
;
de Freitas, Isabel C.
;
Alves, Tiago V.
;
Ando, Romulo A.
;
Fang, Zebo
;
Camargo, Pedro H. C.
Número total de Autores: 6
|
| Tipo de documento: | Artigo Científico |
| Fonte: | CHEMISTRY-A EUROPEAN JOURNAL; v. 23, n. 30, p. 7185-7190, MAY 29 2017. |
| Citações Web of Science: | 5 |
| Resumo | |
In hybrid materials containing plasmonic nanoparticles such as Au and Ag, charge-transfer processes from and to Au or Ag can affect both activities and selectivity in plasmonic catalysis. Inspired by the widespread utilization of commercial Si wafers in surface-enhanced Raman spectroscopy (SERS) studies, we investigated herein the effect of the native SiO2 layer on Si wafers over the surface plasmon resonance (SPR)-mediated activities of the Au and Ag nanoparticles (NPs). We prepared SERS-active plasmonic comprised of Au and Ag NPs deposited onto a Si wafer. Here, two kinds of Si wafers were employed: Si with a native oxide surface layer (Si/SiO2) and Si without a native oxide surface layer (Si). This led to Si/SiO2/Au, Si/SiO2/Ag, Si/Au, and Si/Ag NPs. The SPR-mediated oxidation of p-aminothiophenol (PATP) to p,p'-dimercaptoazobenzene (DMAB) was employed as a model transformation. By comparing the performances and band structures for the Si/Au and Si/Ag relative to Si/SiO2/Au and Si/SiO2/Ag NPs, it was found that the presence of a SiO2 layer was crucial to enable higher SPR-mediated PATP to DMAB conversions. The SiO2 layer acts to prevent the charge transfer of SPR-excited hot electrons from Au or Ag nanoparticles to the Si substrate. This enabled SPR-excited hot electrons to be transferred to adsorbed O-2 molecules, which then participate in the selective oxidation of PATP to DMAB. In the absence of a SiO2 layer, SPR-excited hot electrons are preferentially transferred to Si instead of adsorbed O-2 molecules, leading to much lower PATP oxidation. (AU) | |
| Processo FAPESP: | 15/21366-9 - Materiais híbridos contendo nanopartículas metálicas para aplicações catalíticas |
| Beneficiário: | Pedro Henrique Cury Camargo |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |