Visible light mediated photocatalytic degradation of gaseous trichloroethylene and dimethyl sulfide on modified titanium dioxide

All modified photocatalysts showed a shift in UV-vis absorbance towards higher wavelengths, up to λ = 620 nm. Photocatalytic activity under near-UV and visible light irradiation was systematically investigated through the degradation of gaseous trichloroethylene (TCE) and dimethyl sulfide (DMS) in a batch reactor. Although TiO2 Degussa P25 showed 1.3-6.6 times higher TCE degradation rates than modified photocatalysts under near-UV irradiation, no significant activity was observed at λ > 400 nm. In contrast, modified catalysts showed photocatalytic activity under both blue (400-540 nm) and yellow light (480-720 nm) irradiation, with S-doped TiO2-PM and S-doped TiO2-SG giving the highest TCE degradation rates, respectively. Under daylight irradiation (400-720 nm), S-doped TiO2-PM yielded the highest activity towards both TCE and DMS degradation, exemplified by removal efficiencies higher than 99% within 110 min of irradiation at concentrations up to 537 ppmv.