Preparation of Cu-Doped TiO2 Photocatalyst with Thermal Plasma Torch for Low-Concentration Mercury Removal

Received: July 25, 2012
Revised: November 19, 2012
Accepted: November 19, 2012
Download Citation: RIS|BibTeX|https://doi.org/10.4209/aaqr.2012.07.0196  

Cite this article:
Tsai, C.Y., Hsi, H.C., Kuo, T.H., Chang, Y.M. and Liou, J.H. (2013). Preparation of Cu-Doped TiO2 Photocatalyst with Thermal Plasma Torch for Low-Concentration Mercury Removal. Aerosol Air Qual. Res. 13: 639-648. https://doi.org/10.4209/aaqr.2012.07.0196

ABSTRACT

A high-quality, Cu-doped TiO₂ photocatalyst was prepared via a single-step process using an atmospheric-pressure plasma torch system. Degussa P-25 was thermally doped with Cu at Cu/(Cu + TiO₂) ratios of 0–5 wt.%. The raw and resulting nanoparticles were characterized using TEM, XRD, UV-Vis, and XPS. TEM showed that the particle size of plasma-treated TiO₂ was generally < 50 nm. 67–75% of the resulting particles, by number were between 10 and 20 nm. The remaining particles were < 10 nm (~10%) and between 20 and 30 nm (~10%). The XRD results showed that Cu doping decreased the anatase/rutile crystalline ratio compared to untreated P-25. Nevertheless, the greater the amount of Cu added, the greater the anatase/rutile ratio was for the Cu-doped TiO₂. The UV-Vis results showed that the absorption wavelength for plasma-treated TiO₂ extended to the visible light range, especially for TiO₂ doped with 5 wt.% Cu. The XPS results revealed that the form of Ti was Ti³⁺ and Ti⁴⁺, O was O^2–, and Cu was Cu⁺ and Cu²⁺. The Hg⁰ breakthrough tests indicated that the Cu-doped TiO₂ underwent appreciable Hg⁰ removal under visible-light irradiation. Doped Cu effectively suppressed Hg reemission from the TiO₂ surface.

Keywords: Visible-light photocatalyst; Metal doping; Plasma torch; Hg