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

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.