A Ag synchronously deposited and doped TiO₂hybrid as an ultrasensitive SERS substrate: a multifunctional platform for SERS detection and photocatalytic degradation

Abstract

Ag simultaneously deposited and doped TiO2 (Ag-TiO2) hybrid nanoparticles (NPs) were prepared via a sol-hydrothermal method, as both a sensitive surface-enhanced Raman scattering (SERS) substrate and a superior photocatalyst for the first time. Ag-TiO2 hybrid NPs exhibit excellent SERS performance for several probe molecules and the enhancement factor is calculated to be 1.86 × 105. The detection limit of the 4-mercaptobenzoic acid (4-MBA) probe on the Ag-TiO2 substrate is 1 × 10-9 mol L-1, which is four orders of magnitude lower than that on pure TiO2 as a consequence of the synergistic effects of TiO2 and Ag. This is the highest SERS sensitivity among the reported semiconductor substrates and even comparable to noble metal substrates, and a SERS enhancement mechanism from the synergistic contribution of the semiconductor and noble metal was proposed. And importantly, the Ag-TiO2 hybrid shows excellent photocatalytic degradation activity for the detected species under UV light irradiation at lower concentration conditions, even for the hard to degrade 4-MBA molecule. This makes the Ag-TiO2 hybrid promising as a dual-function platform for both highly sensitive SERS detection and photocatalytic degradation of a pollutant system. Moreover, it also proves that the Ag-TiO2 hybrid can serve as a promising recyclable SERS-active substrate by virtue of its photocatalytic self-cleaning properties for some specific applications, for instance comparative studies of different species on the same SERS platform, in addition to the economic benefit.

Irreversible accumulated SERS behavior of the molecule-linked silver and silver-doped titanium dioxide hybrid system

“…1-3. The strong absorption occurs between 400 and 800 nm, the diffraction peaks emerged and shifted, and the change of chemical state and binding energy all reveal that deposition and doping of Ag are simultaneously exist in the Ag/Ag-doped TiO 2 nanostructure 25,[31][32][33] . The detailed analysis are contained in Supplementary Note 1.…”

An Experimental and Theoretical Study on the Effect of Silver Nanoparticles Concentration on the Structural, Morphological, Optical, and Electronic Properties of TiO2 Nanocrystals

“…For example, some studies have used a chemical reduction method by doping Ag + into TiO 2 NPs [18,22]. Yang et al used a photo reduction method of silver nitrate (AgNO 3 ) by using TiO 2 NPs under UV light [23]. Zhou et al fabricated Ag/Ag-doped TiO 2 using modified sol-hydrothermal method with the assistance of NaOH additive [24].…”

Control of Volume‐Responsive Properties of Hydrogels through Molybdenum Disulfide Nanosheet Incorporation

“…[37] Also, it should be noted that previous studies utilized MoS 2 mostly in optical or electrochemical applications. [41] The absorbance increased linearly with the amount of MBAMS, following Lambert-Beer behavior, which implies uniform dispersion of MBAMS without aggregation in the deionized (DI) water solvent (Figure 2c, inset). [39] The optical properties of MBAMS solution were observed by ultraviolet-visible spectroscopy (UV-vis) and Fourier-transform infrared spectroscopy (FT-IR).…”