The synthesis and coating process of TiO₂ nanoparticles using CVD process

A chemical vapor deposition (CVD) process with T-junction apparatus was used to coat a TiO₂ photocatalyst onto a glass bead. The amount of coating was controlled using the coating time. The coated bead catalysts were characterized using various techniques, such as scanning electron microscopy, Brunauer-Emmett-Teller, X-ray diffraction and X-ray photoelectron spectroscopy. The CVD technique was compared with the dip coating method using the commercial catalyst, P-25. The CVD-coated bead had a comparatively uniform and regular surface, while the dip-coated bead showed a partly un-coated surface. Additionally, the catalytic activity was investigated using the TiO₂ coated beads as the photocatalyst in the decomposition of acetaldehyde. The result showed that a 60-min sample coating time gave the best photocatalytic activity.