Effect of post-annealing treatment on structural, optical and photocatalytic properties of TiO2 nanoparticles prepared via pulsed laser ablation in liquid

Ultrasmall TiO2 nanoparticles were synthesized through pulsed laser ablation of a metal titanium target in liquid followed by thermal annealing treatment. The impact of post-annealing treatment on the structural, morphological, optical properties, and the photocatalytic activity of the synthesized TiO2 nanoparticles have been investigated through a variety of analytical techniques, including X-Ray diffraction, transmission electron microscopy, ultraviolet-visible diffusion reflectance spectra, X-ray photoelectron spectroscopy. The results reveal that annealing temperature significantly improved the crystallinity of laser ablated TiO2 nanoparticles and modified the chemical states of surface elements. Defects introduced by laser ablation, which serve as electron traps, combined with enhanced crystallinity resulting from thermal annealing, have improved the photocatalytic degradation performance of TiO2 nanoparticles. Specifically, TiO2 nanoparticles annealed at 300 ℃ exhibited optimal photocatalytic performance in decomposition of model dye under the irradiation from xenon lamp, demonstrating the critical role of annealing in improving photocatalytic properties. This study not only broadens the comprehension of the impact of post-treatment on the characteristics of laser-ablated TiO2 nanoparticles nanoparticles but also highlights their potential for effective wastewater remediation.