Fabrication of SiO₂/Al₂O₃ Composite-Coated TiO₂ by Pulsed Chemical Vapor Deposition and Its Applications

Abstract

Surface modification is required for various applications of titanium dioxide (TiO 2 ) to suppress the photoactivity of TiO 2 . In this work, a composite SiO 2 /Al 2 O 3 film was successfully deposited onto TiO 2 particles by pulsed chemical vapor deposition. The composite film was particularly dense and uniform, as it was constituted by the 4.17 nm SiO 2 and 1.62 nm Al 2 O 3 amorphous films. The photocatalytic process with coated TiO 2 was investigated. The enhanced rate of carrier recombination in SiO 2 /Al 2 O 3coated TiO 2 was the main cause of inhibited photoactivity, which was mainly contributed by the inner SiO 2 film. TiO 2 /SiO 2 and TiO 2 /SiO 2 /Al 2 O 3 presented outstanding pigmentary properties. Compared to naked TiO 2 , TiO 2 /SiO 2 /Al 2 O 3 was more conducive to the weatherability of polyvinyl chloride and waterborne paints, owing to the suppressed photoactivity of the SiO 2 film and the increased optical absorption of the outer Al 2 O 3 film. The pulsed chemical vapor deposition showed promising industrial application potential for TiO 2 surface modification.

Simulation of a microstructure fiber glycerol sensor based on lossy mode resonance

“…The diameter of the fiber core is 11 um, and the spacing of the air holes is 2.5 um. Hydrofluoric acid (HF) is used to etch air holes in optical fibers [18], while sensing materials can be coated on the fiber surface by chemical vapor deposition [19]. The theoretical simulation is supported by COMSOL Multiphysics, and there are 112978 mesh cells and 10846 boundary elements for this sensor's model.…”