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On the Effect of Native SiO2 on Si over the SPR-mediated Photocatalytic Activities of Au and Ag Nanoparticles.
- Source :
-
Chemistry - A European Journal . 5/29/2017, Vol. 23 Issue 30, p7185-7190. 6p. - Publication Year :
- 2017
-
Abstract
- 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 O2 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 O2 molecules, leading to much lower PATP oxidation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09476539
- Volume :
- 23
- Issue :
- 30
- Database :
- Academic Search Index
- Journal :
- Chemistry - A European Journal
- Publication Type :
- Academic Journal
- Accession number :
- 123283631
- Full Text :
- https://doi.org/10.1002/chem.201700651