Growth characteristics of TiO2 films synthesized by fluidized bed atomic layer deposition

TiO₂ is an ultra-wide bandgap semiconductor with excellent physical properties and promising applications in photocatalysis and photo-electrocatalysis. Fluidized bed atomic layer deposition (FBALD) is an effective method for depositing TiO₂ films, offering precise thickness control. This study presents a comprehensive investigation into the growth characteristics and properties of TiO₂ films on SiO₂ particles prepared via FBALD, with a focus on the impact of cycle number, temperature, precursor concentration, pulse time, purge time and precursor component. The TEM images indicate that continuous and uniform TiO₂ films are formed at 120 °C and 180 °C, whereas dispersed nanoscale TiO₂ islands are observed at 240 °C and 300 °C. By increasing precursor supply or reducing N₂ purge time, the film growth rate significantly increases. Additionally, increasing the precursor pulse time has a stronger effect on film growth, while decreasing the N₂ purge time leads to more uneven film thickness growth. The core-shell structured SiO₂@TiO₂ photocatalysts synthesized using TiCl₄ and TTIP as precursors both exhibit good photocatalytic degradation performance that, under 300 W xenon lamp irradiation for 60 min, the degradation efficiency of tetracycline hydrochloride (TC) reaches 95 % and 90 %, respectively. This performance surpasses that of catalysts prepared by solution impregnation method under the same mass fraction.