Effect of Ag Modification on the Structure and Photocatalytic Performance of TiO2/Muscovite Composites

Abstract

Ag/TiO2/muscovite (ATM) composites were prepared by the sol–gel method and the effects of Ag modification on the structure and photocatalytic performance were investigated. The photocatalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area (BET), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FTIR), photoluminescence spectra (PL) and ultraviolet–visible diffuse reflectance spectra (DRS). The photocatalytic activity of the obtained composites was evaluated by taking 100 mL (10 mg/L) of Rhodamine B (RhB) aqueous solution as the target pollutant. The muscovite (Mus) loading releases the agglomeration of TiO2 particles and the specific surface area increases from 17.6 m2/g (pure TiO2) to 39.5 m2/g (TiO2/Mus). The first-order reaction rate constant increases from 0.0009 min−1 (pure TiO2) to 0.0074 min−1 (150%TiO2/Mus). Ag element exists in elemental silver. The specific surface area of 1-ATM further increases to 66.5 m2/g. Ag modification promotes the separation of photogenerated electrons and holes and increases the visible light absorption. 1%Ag-TiO2/Mus (1-ATM) exhibits the highest photocatalytic activity. After 100 min, the rhodamine B (RhB) degradation degrees of PT, 150%TiO2/Mus and 1-ATM are 10.4%, 48.6% and 90.6%, respectively. The first-order reaction rate constant of 1-ATM reaches 0.0225 min−1, which is 25 times higher than that of pure TiO2.

Antibacterial Activity of Visible Light Responsive‐Silver‐Nanoparticle/Titania Composite Thin Films with Unprecedently Higher Amounts of Silver

“…The absorption band seen in this location can be attributed to the distinctive surface plasmon resonance (SPR) of silver nanoparticles (Ag NPs). [ 6–9 ]…”

“…The surface plasmon resonance (SPR) generates huge fluctuating electric fields around and between metal nanoparticles when samples are treated by visible light. [ 8,9 ] Numerous studies have established a correlation between broad absorption and point‐to‐tip plasmonic styles, intraparticle plasmon coupling of tip and cavity resonances, as well as incident light scattering. [ 48,49 ] Therefore, the wide‐range vis‐region absorption may be related to the distinctive SPR of metallic Ag NPs in the TiO 2 matrix.…”

“…Previous research suggests that DNA replication is affected, and cellular proteins become inactive when exposed to silver ions. [ 8 ] According to current evidence, higher concentrations of Ag 0 do not interact with cytoplasmic components and nucleic acids. [ 41 ] The antibacterial properties of silver nanoparticles (Ag‐NPs) with a diameter of about 24 nm against Gram‐negative bacteria were reported in reference.…”

“…When silver nanoparticles (Ag‐NPs), were added to a transparent titania matrix, the surface plasmon resonance (SPR) of the metallic particles was observed to increase additively. [ 6–9 ] As a result, an absorption peak emerged in the visible range of the metal/transparent matrix composite's optical spectrum. The SPR is known to increase the photo responsiveness of TiO 2 , hence promoting bactericidal activity.…”