Improving SERS Sensing Efficiency and Catalytic Reduction Activity in Multifunctional Ternary Ag-TiO₂-GO Nanostructures: Roles of Electron Transfer Process on Performance Enhancement

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.

Photoinduced Enhanced Raman Spectroscopy for the Ultrasensitive Detection of a Low-Cross-Section Chemical, Urea, Using Silver–Titanium Dioxide Nanostructures

“…However, the cross section can be enlarged by increasing the rate of CT . In a 2021 study, we designed an experimental model using methylene blue as the analyte to prove that Ag/TiO 2 contacts in Ag/TiO 2 nanocomposites could enhance electron transfer, leading to improvement of the SERS intensity . Therefore, in the effort of improving the performance of SERS sensors for urea, we utilized a set of Ag/TiO 2 nanocomposites with different TiO 2 contents.…”

“…Ag/TiO 2 nanocomposites were prepared via a facile wet chemistry method, as described in Scheme and in detail in our previous study . TiO 2 NPs were synthesized using a modified sol–gel method from TiCl 4 precursors .…”

“…Ag/TiO 2 nanocomposites were prepared via a facile wet chemistry method, as described in Scheme 1 and in detail in our previous study. 35 TiO 2 NPs were synthesized using a modified sol−gel method from TiCl 4 precursors. 36 An AgNO 3 solution was added to a set of variously prepared mixtures containing different amounts of crystalline TiO 2 NPs calcined at 400 °C and 50 mL of C 2 H 5 OH.…”

Paper/GO/e-Au flexible SERS sensors for in situ detection of tricyclazole in orange juice and on cucumber skin at the sub-ppb level: machine learning-assisted data analysis

“…Pristine GO was synthesized using a modified Hummers' method, resulting in a sheet-like structure, which was report in our 2021 study. 50 GO and e-AuNPs were mixed together at different ratios, including 1, 2, 3, 4 and 5 wt% of GO. Subsequently, the mixture underwent sonication for 30 min, allowing the anchoring of e-AuNPs onto the GO surface.…”

Simulation Calculation Verification of Graphene Oxide-Decorated Silver Nanoparticles Growing on Titania Nanotube Array as SERS Sensor Substrate

“…Our previous works had proven that GO modification of Ag/TiO 2 NTA could be used for SERS-sensing detection of organic aromatic ring molecules [23]. It is believed that GO/Ag/TiO 2 becomes a reasonable choice as a SERS substrate [24,25].…”