Fabrication of Al-Doped TiO₂Visible-Light Photocatalyst for Low-Concentration Mercury Removal

Abstract

High-quality Al-doped TiO2visible-light photocatalyst was prepared via a single-step direct combination of vaporized Ti, Al, and O2using a 6 kW thermal plasma system. Results showed that the formed Al-doped TiO2nanoparticles were a mixture of anatase and rutile phase and had a size between 10 and 105 nm. The absorption spectra of the nanoparticles shifted towards the visible light regions, depending on the Al2O3addition. Ti4+and Ti3+coexisted in the synthesized Al-doped TiO2; the Ti3+concentration, however, increased with increasing Al2O3addition due to Al/Ti substitution that caused the occurrence of oxygen vacancy. Hg0breakthrough tests revealed that the nanoparticles had an appreciable Hg0removal under visible-light irradiation. Nevertheless, moisture reduced Hg removal by the nanoparticles, especially when visible-light irradiation was applied, suggesting that the competitive adsorption between H2O and Hg species on the active sites of TiO2surface occurred.

Influence of electronic structures of doped TiO2on their photocatalysis

“…Al doping effects were studied by many researchers [102][103][104][105][106]. Shirley et al studied electronic and optical properties of Al-doped anatase and rutile TiO 2 from ab initio calculations [107].…”

A review on removal of elemental mercury from flue gas using advanced oxidation process: Chemistry and process

“…In addition, Yuan et al 1193 2012d and 2012e investigated the effect of UV intensity on Hg 0 removal using TiO 2 -aluminum silicate fiber with 1194 UV irradiation, and the results indicated that UV irradiation was critical to the successful oxidation of Hg 0 , and 1195with the decrease of UV intensity, photocatalytic oxidation efficiency for Hg 0 evidently reduced due to the 1196 reduction of photoexcited active species. In addition, Hsi(2012) andTsai (2011Tsai ( , 2012 synthesized oxygen-vacant , mechanism and kinetics of Hg 0 removal using TiO 2 photocatalytic AOTs 1201 3.7.1 Products of Hg 0 removal using TiO 2 photocatalytic AOTs 1202The products of Hg 0 removal using TiO 2 photocatalytic oxidation are important information for the recovery 1203 of mercury resources and avoiding new secondary mercury contamination Wu et al 1998. determined the reaction 1204 products of Hg 0 removal by in situ-generated TiO 2 with UV irradiation using the combination of XRD and 1205 electron dispersive X-ray spectroscopy (EDS).…”

Photoelectrochemical performance of dye sensitized solar cells based on aluminum-doped titanium dioxide structures

“…1(c)) of the Al-doped TNPWs contains TNPs and TNWs phases with some additional peaks. The additional peaks at 35.151, 43.351, 52.501 and 57.501 are indexed to the Al phase [29]. When the Al-doped level is 20%, the sample has an obvious characteristic peak (1 1 À 1) at 35.151, which confirms the formation of Al phase with monoclinic crystal structure [30].…”