Preparation of transparent nanostructured N-doped TiO2 thin films by combination of sonochemical and CVD methods with visible light photocatalytic activity

Abstract

Pollution of water resources with pesticide compounds has raised serious environmental problems, and for photocatalytic degradation of these pollutants, thin film photocatalysts are preferred to colloidal ones due to the separation problem of colloidal nanoparticles. In this work, nanostructured TiO 2 and N-doped TiO 2 thin films with high transparency were deposited on glass and quartz substrates through sonochemical-chemical vapor deposition (CVD) method. The films prepared on glass and quartz substrates had nanocubic and nanospherical morphology, respectively. The presence of N atoms in the structure of TiO 2 resulted in a decrease in the band gap energy of TiO 2 and also in the reduction of photogenerated electron-hole recombination rate. Furthermore, the presence of N atoms induced the formation of Ti 3+ species which can act as hole trapping centers. The prepared thin films were also used for the visible light photocatalytic degradation of paraoxon pesticide. According to these results among the prepared thin films, the N-doped TiO 2 thin films have higher photocatalytic activity than pure TiO 2 thin films. Moreover, in comparison with the thin films deposited on quartz substrate, the films on glass substrate have higher photocatalytic performance, which can be related to the special nanocubic morphology of these samples.

Photocatalytic activity of graphene oxide–TiO 2 thin films sensitized by natural dyes extracted from Bactris guineensis

“…Rasoulnezhad et al . [74] reported the formation of Ti 3+ species in N-doped TiO 2 thin films deposited by chemical vapour deposition. The formation of O v and Ti 3+ could act as electron traps and inhibit the recombination process.…”

“…Figure8aalso shows a red shift displacement of the spin to peak 0.6 eV, indicating the possibility of appearance of Ti 3þ and that, under synthesis conditions, carbon tends to react with oxygen in the TiO 2 lattice leading to the formation of oxygen vacancies (O v ) and the low valence state of Ti 3þ[73]. Rasoulnezhad et al[74] reported the formation of Ti 3þ species in N-doped TiO 2 thin films deposited by chemical vapour deposition. The formation of O v and Ti 3þ could act as electron traps and inhibit the recombination process.…”

Photocatalytic degradation of Perchloroethylene by a lab-scale continuous-flow annular photoreactor packed with glass beads carbon-doped TiO2 nanoparticles

“…Although TiO 2 itself has been proved to be a suitable photocatalyst for oxidation of PCE through PCO, more efforts are needed for further improvement of photocatalytic performance of TiO 2 -based catalysts. Supporting on materials with large surface areas such as glass fiber [15], paint [16], thin-film TiO 2 [17], TiO 2 pellet [18], carbon black or activated carbon [19], carbon nanofibers [20], carbon nanotube [21] is one approach. Another trend is combining or doping TiO 2 with other materials such as Ag [22], Au [23], Sn [24], Pb [25], Ni [26] metal oxides [27] to improve the performance of the photocatalyst.…”

Bi@Bi4Ti3O12/TiO2 films on glass with photocatalytic and self‐cleaning performance

“…In the meantime, there have also been several reports on preparation and photocatalytic activity of the TiO 2 based transparent thin films, such as the S‐doped TiO 2 , Fe‐doped TiO 2 and N‐doped TiO 2 . These films were prepared by the methods of ultrasonic assisted spray pyrolysis technique and combination of sonochemical and CVD processes . These reports concluded that the element‐doped TiO 2 films had highly uniform surfaces and good photocatalytic activities or self‐cleaning potential.…”

“…These films were prepared by the methods of ultrasonic assisted spray pyrolysis technique and combination of sonochemical and CVD processes. [39][40][41] These reports concluded that the element-doped TiO 2 films had highly uniform surfaces and good photocatalytic activities or self-cleaning potential. In comparison, the Bi@Bi 4 Ti 3 O 12 /TiO 2 (X-Y) films prepared in this work, showed a strong photocatalytic activity under visible light treatments and displayed a translucent feature.…”