The effect of the surface disordered layer on the photoreactivity of titania nanoparticles

Self-cleaning building materials: The multifaceted effects of titanium dioxide

“…This analysis showed that only for nanoparticles immersed in nitric acid an average decrease in corresponding crystallite size of 2 nm was observed, indicating the presence of an amorphous layer around the particle, while no change was found in the other materials: this further supports XRD results, which indicate a lower crystallinity of the N-T sample. As previously proposed, and supported by further research works, the amorphization is ascribed to surface protonation of the oxide in acid environment [35,52,53]. Table 2 -TEM analyses of P25 powders before treatment, after acid treatment and after neutralization (labels recall Table 1 although samples do not contain paint) and difference between TEM bright field and dark field particle size, corresponding to the difference between actual particle size and size of corresponding crystal domain.…”

Unconventional Route to Oxygen‐Vacancy‐Enabled Highly Efficient Electron Extraction and Transport in Perovskite Solar Cells

“…[12] These chains are characteristic of amorphous TiO 2 ,p articularly at the boundaries of adjacent crystalline TiO 2 nanoparticles. [13] Thus,t he formation of adenser mesoporous HCl-treated TiO 2 film can be attributed to the reorganization of the Ti-O chains by acid that generates an amorphous TiO 2 buffer layer (marked in red;i nset in the lower right panel in Figure 1a)i ntimately situated on the surface of crystalline TiO 2 nanoparticles (marked in green). [14] XPS measurement was conducted to determine the changes of TiO 2 surface states.F igure 2a compares the Ti 2p and O1sc ore level spectra of pristine anatase TiO 2 ,a nd anatase TiO 2 after HCl treatment (denoted TiO 2 -HCl) without and with subsequent plasma exposure.W en ote that O 2 plasma treatment was performed because the TiO 2 -HCl film contains both surface and bulk (within TiO 2 nanoparticle; lower right in Figure 1a)o xygen vacancies,b oth of which increase the donor density of TiO 2 when employed as the ETL in PSC.…”

Determination of the crystallinity of TiO2 photocatalysts

“…The fraction of crystalline anatase contained in samples prepared by https://doi.org/10.1016/j.jphotochem.2018.08.042 T different routes has been often evaluated with respect to the integral intensity of the (101) diffraction peak of selected samples assumed as 100% crystalline [28][29][30]. Recent papers have reported quantitative analyses of the crystallinity of TiO 2 powders [31][32][33][34][35][36][37][38][39][40]. In particular, the absolute crystallinity of anatase and rutile was calculated according to a theoretical method proposed by Jensen et al [31] while a different approach, based on the XRD patterns of natural crystals, was followed for brookite [36].…”