Abstract
Multifunctional nanocomposites have received great attention for years; electron transfer (ET) is considered as an explanatory mechanism for enhancement of performance of these nanostructures. The existence of this ET process has been proved in many studies using either experimental or computational approaches. In this study, a ternary nanocomposite system of Ag/TiO2/GO was prepared to evaluate the performance enhancement in two experimental models: a physical model (i.e., surface-enhanced Raman scattering (SERS) sensor) and a chemical one (i.e., catalytic reduction reaction). The metal/semiconductor heterojunction between Ag and TiO2, as well as Ti-O-C bonds, has allowed plasmonic hot electrons to be transferred in the internal structure of the material. An investigation on the role of Ag content on the SERS sensing and catalytic reduction efficiency of Ag/TiO2/GO was performed in both models. Interestingly, they all resulted in the same optimal Ag content of 50 wt%. It was then further discussed to provide a convincing evidence for the plasmon-induced electron transfer phenomena in the Ag/TiO2/GO nanostructure. These findings also suggest a pathway to design and develop high-performance, cost-effective, facile-preparation, and eco-friendly multifunctional nanostructures for detecting and removing contaminants in environment.
Highlights
It is widely accepted that electron-transfer (ET) mechanism in metal-semiconductor (MS) nanocomposites/nanohybrids must be involved to explain the enhancement of their contaminant detection/degradation performance, in comparison to single metals or semiconductors [1,2,3,4,5]
Localized surface plasmon resonance (LSPR) of the metal plays a central role in the generation of hot electrons when
The assynthesized Ag/TiO2 NPs were self-assembled onto the surface of the graphene oxide (GO) sheets via electrostatic interactions
Summary
It is widely accepted that electron-transfer (ET) mechanism in metal-semiconductor (MS) nanocomposites/nanohybrids must be involved to explain the enhancement of their contaminant detection/degradation performance, in comparison to single metals or semiconductors [1,2,3,4,5]. In MS materials, ET process takes place in a dualmode pathway. It means electrons can be transferred from metals to semiconductors or from semiconductors to metals, which depends directly on the wavelengths of excitation sources [2,3,4, 6]. When a metal nanostructure contacts with a semiconductor, a specific space-charge region is created in MS interface, which leads to the band bending in the semiconductor and gives rise to a Schottky transition [2, 6]. Due to the light-matter interaction between ultraviolet (UV) light and the semiconductor, electrons are excited and they can be injected into the metal via the Schottky transition, causing the increase of the electron lifetime [6]. Localized surface plasmon resonance (LSPR) of the metal plays a central role in the generation of hot electrons when
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