Experimental study of the visible-light photocatalytic activity of oxygen-deficient TiO₂prepared with Ar/H₂plasma surface treatment

Abstract

Oxygen-deficient TiO 2 (TiO 2%x ) has been proposed as a visible-light-responsive photocatalyst. TiO 2%x thin films were prepared by Ar/H 2 plasma surface treatment, applying varying levels of microwave input power and processing times. The highest visible light photocatalytic activity was observed when using an input power of 200 W, a plasma processing time of 10 min, and a 1 : 1 Ar : H 2 ratio, conditions that generate an electron temperature of 5.7(+1.0) eV and an electron density of 8.5 ' 10 10 cm %3 . The maximum formaldehyde (HCHO) removal rate of the TiO 2%x film was 2.6 times higher than that obtained from a TiO 2%x N x film under the same test conditions.

Visible and infrared photocatalytic activity of TiO thin films prepared by reactive sputtering

“…However, for practical application, TiO x thin films are more adequate than powders. Several methods can be used to prepare TiO x thin films, such as blow arc discharge [19], pulsed laser deposition [20], plasma assisted chemical vapor deposition [21,22], plasma surface treatment [23], anodization [24] and reactive magnetron sputtering [25][26][27]. Among these methods, the magnetron sputtering method allows an easy control of the films structure and composition besides provides many advantages in reproducibility, high mechanical durability, strong adhesion and uniformity and it is applicable to large area deposition.…”

“…Nakano et al [23] reported visible light photocatalytic activity of of oxygen deficient TiO 2 films obtained by Ar/H 2 plasma surface treatment; Dong et al [24] anodization for visible light photocatalysis; Lee et al [26] grew N-doped TiO x films using reactive sputtering reporting a red-shift band gap; and Leichweiss et al [20] grewn highly nonstoichiometric TiO x thin films, that shown high efficiency for water splitting reaction, using pulsed laser deposition at room temperature. Related to the activation of TiO 2 by infrared radiation, we only found the work of Gannoruwa et al [28], they reported that the nanocomposite Ag 2 O/TiO 2 was infrared active in the range from 800 nm to 1200 nm.…”