Application of pulsed chemical vapor deposition on the SiO2-coated TiO2 production within a rotary reactor at room temperature

Abstract Pulsed chemical vapor deposition (P-CVD) is a promising technology for the surface modification of TiO2 particles. For the scale-up application of P-CVD, a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work. The obtained SiO2-coated TiO2 particles were characterized by various measures including high-resolution transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, etc. The results illustrated that the SiO2 films with a thickness of (3.7±0.7) nm were successfully deposited onto the surface of TiO2 particles. According to the dye degradation tests and acid solubility measurement, the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO2 particles. Zeta potential measurements showed that the SiO2-coated TiO2 is possible to be stably dispersed in the pH range of 6.9–11.6. The coating process made the whiteness of TiO2 particles decreased slightly but still sufficient (97.3±0.1) for application. Furthermore, the properties of the TiO2 particles coated by P-CVD were compared with the particles coated by traditional wet chemical deposition. It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance. The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO2-coated TiO2 via P-CVD.