Biomimetic Synthesis of TiO₂–SiO₂–Ag Nanocomposites with Enhanced Visible-Light Photocatalytic\nActivity

Abstract

Ternary\nTiO₂–SiO₂–Ag nanocomposites\nwith enhanced visible-light photocatalytic activity have been synthesized\nthrough a facile biomimetic approach by utilizing lysozyme as both\ninducing agent of TiO₂ and reducing agent of Ag⁺. TiO₂ nanoparticles (∼280 nm) are at first fabricated\nby the inducing of lysozyme. Afterward, SiO₂ layers are\nformed as “pancakes” stuck out of TiO₂ nanoparticles\nthrough a sol–gel process. Finally, Ag nanocrystals (∼24.5\nnm) are deposited onto the surface of TiO₂–SiO₂ composites via the reduction of lysozyme, forming TiO₂–SiO₂–Ag nanocomposites. The resultant\nnanocomposites display a high photocatalytic activity for the degradation\nof Rhodamine B under the visible-light irradiation, which can be attributed\nto the synergistic effect of enhanced photon absorption from the surface\nplasma resonance of Ag nanocrystals and the elevated adsorption capacity\nfor Rhodamine B from the high specific surface area of SiO₂. This study may provide some inspiration for the rational design\nand the facile synthesis of composite catalysts with a high and tunable\ncatalytic property through a green, efficient pathway.