Double Metal Co-Doping of TiO₂Nanoparticles for Improvement of their SERS Activity and Ultrasensitive Detection of Enrofloxacin: Regulation Strategy of Energy Levels

Abstract

In this paper, the strategy of double metals (Ni and Zn) codoping was carried out for improving SERS activity of TiO 2 nanoparticles (NPs). Accordingly, pure TiO 2 and different metals doped TiO 2 (Zn-TiO 2 , Ni-TiO 2 and NiÀZn-TiO 2 ) NPs substrates were synthesized by a sol-hydrothermal method. The results show that, compared to the other substrates, 4-mercaptobenzoic acid (4-MBA) probe molecules on the NiÀZn-TiO 2 exhibit the largest SERS enhancement, which is attributed to the contributions of double metals codoping. Ni and Zn codoping can simultaneously result in the abundant surface state levels and metal doping levels in the TiO 2 band gap; both of them together promote the charge transfer from TiO 2 to molecule and consequent SERS enhancement of probe molecule. And importantly, NiÀZn-TiO 2 NPs can be served as the efficient SERS-active substrate for the detection of enrofloxacin (ENR) drug. Under the optimal test conditions, the limit of detection of ENR on the 1 %Ni-1 %Zn-TiO 2 substrate can be reduced to 3 3 10 À10 M, which is far lower than the standard of European Union, and there is a good linear relationship in the wide low concentration range of 1 3 10 À4~1 3 10 À9 M.[a] Dr.

Dual Functional Ta-Doped Electrospun TiO2 Nanofibers with Enhanced Photocatalysis and SERS Detection for Organic Compounds

“…in TiO 2 have shown enhanced photocatalytic properties due to the improved optical and charge separation ability of the doped TiO 2 through the production of surface defects. Additionally, these doped TiO 2 materials show the enhanced SERS functionality toward the organic molecules. − Similarly, Ni and Zn codoping in TiO 2 has shown to create abundant surface states and metal doping levels band gap, which facilitates the charge transfer from TiO 2 to the probe molecule and enhances the SERS sensitivity …”

“…24−26 Similarly, Ni and Zn codoping in TiO 2 has shown to create abundant surface states and metal doping levels band gap, which facilitates the charge transfer from TiO 2 to the probe molecule and enhances the SERS sensitivity. 27 Other dopants such as Nb, Ta, etc., have been extensively used in improving the properties of TiO 2 for various applications ranging from photocatalysis to photovoltaic devices. However, Ta doping has advantage over Nb doping owing to its higher equilibrium solubility within TiO 2 network because of lower energy requirement.…”

Recent Development of SERS Technology: Semiconductor-Based Study

“…Researchers have observed strong SERS signals from some semiconductor nanomaterials, such as ZnO, ZnS, Pb 3 O 4 , CuO, CdTe, and TiO 2 (Figure 1), 8 and they initially carried out studies on ion-doped semiconductors as SERS substrates. 9 Based on the study of pure semiconductor materials, several semiconductor-doped SERS substrates, such as doped ZnO and doped TiO 2 , were synthesized and prepared. Satisfactory SERS activity is easily achieved by a doped semiconductor by changing the doping species and ion content to change the surface defect concentration and band gap of semiconductor nanoparticles.…”

“…Researchers have observed strong SERS signals from some semiconductor nanomaterials, such as ZnO, ZnS, Pb 3 O 4 , CuO, CdTe, and TiO 2 (Figure ), and they initially carried out studies on ion-doped semiconductors as SERS substrates . Based on the study of pure semiconductor materials, several semiconductor-doped SERS substrates, such as doped ZnO and doped TiO 2 , were synthesized and prepared.…”

TiO2 Nanofoam–Nanotube Array for Surface-Enhanced Raman Scattering

“…Titanium dioxide (TiO 2 ) is one of the most investigated semiconductors for SERS applications. Zhao et al investigated SERS performance of TiO 2 substrate since 2008 [5][6][7] , reporting that particle size, surface defects, and morphologies have a significant impact on the enhanced Raman scattering of TiO 2 .…”