Rational Design of Ag/TiO₂ Nanosystems by a Combined RF‐Sputtering/Sol‐Gel Approach

Abstract

The present work is devoted to the preparation of Ag/TiO(2) nanosystems by an original synthetic strategy, based on the radio-frequency (RF) sputtering of silver particles on titania-based xerogels prepared by the sol-gel (SG) route. This approach takes advantage of the synergy between the microporous xerogel structure and the infiltration power characterizing RF-sputtering, whose combination enables the obtainment of a tailored dispersion of Ag-containing particles into the titania matrix. In addition, the system's chemico-physical features can be tuned further through proper ex situ thermal treatments in air at 400 and 600 degrees C. The synthesized composites are extensively characterized by the joint use of complementary techniques, that is, X-ray photoelectron and X-ray excited Auger electron spectroscopies (XPS, XE-AES), secondary ion mass spectrometry (SIMS), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), electron diffraction (ED), high-angle annular dark field scanning TEM (HAADF-STEM), energy-filtered TEM (EF-TEM) and optical absorption spectroscopy. Finally, the photocatalytic performances of selected samples in the decomposition of the azo-dye Plasmocorinth B are preliminarily investigated. The obtained results highlight the possibility of tailoring the system characteristics over a broad range, directly influencing their eventual functional properties.

One‐Pot Synthesis of Core‐Shell Silver‐Gold Nanoparticle Solutions and Their Interaction with Methylene Blue Dye

“…The pure Au and Ag colloids showed the greatest propensity for an increase in the extinction coefficient of MB due to an enhanced transfer of the surface plasmons to the localised dye molecules and demonstrated the potential for increased functionality as light-activated agents in the lethal photosensitisation of bacteria. Current research has employed Au and Ag nanoparticles for the enhancement of the optical properties in semiconductor thin films by means of composite formation, [26][27][28][29][30][31][32][33] the destruction of bacteria, [34][35][36][37][38][39][40] photo switches, [41] improvements in the detection of cancer [42] and DNA, [43] and even for single molecule detection by means of surface enhanced Raman spectroscopy (SERS). [44,45] By combining these two metals into a single entity, the catalytic properties can be further enhanced [11] and the localised surface plasmon absorption can be varied continuously between the limits of the monometallic Au and Ag nanoparticles.…”

Synthesis of TiO2 nanofibers with adjustable anatase/rutile ratio from Ti sol and rutile nanoparticles for the degradation of pollutants in wastewater

“…One involves increasing the specific surface area by changing the form of TiO 2 ; the other involves promoting the separation of holes and electrons in TiO 2 through semiconductor composition and doping methods [12][13][14][15][16][17][18][19]. Many researchers have fabricated TiO 2 nanofibers by electrospinning.…”

Study of thermal annealing induced plasmonic bleaching in Ag:TiO2 nanocomposite thin films

“…In literature researchers have studied the effect of thermal annealing on Ag:TiO 2 nanocomposites, but provided different observations [10,12,13]. For example, Okumu et al observed evolution of SPR peak only after annealing with a red shift in peak position when annealing temperature was increased from 300 to 500°C [10].…”

“…In particular, size selective Ag nanoparticles were stabilized by chemical capping [8] as well as in chemically un-reactive dielectric oxide matrices, i.e. SiO 2 [9], TiO 2 [10][11][12][13] and ZrO 2 [14][15][16]. However, the stability of plasmonic properties, a complex phenomena due to inter-dependent processes during the nucleation and growth of nanoparticles (which precisely depends on local environment) needs further investigation with thermal annealing.…”

“…Owing to these, noble metal nanoparticles embedded in dielectric/polymer matrices have been extensively studied to manipulate optical signals on a sub-wavelength scale [8][9][10][11][12][13][14][15][16][17][18]. In particular, size selective Ag nanoparticles were stabilized by chemical capping [8] as well as in chemically un-reactive dielectric oxide matrices, i.e.…”