Synthesis, characterisation and photocatalytic activity of N-doped TiO2–Nb2O5 mixed oxides

Abstract

Nitrogen-doped TiO2 and TiO2–Nb2O5 catalysts were prepared by sol–gel technique using titanium isopropoxide (TIP) and potassium niobate. The obtained samples were subsequently calcined at 380 and 500°C. Undoped TiO2 and TiO2–Nb2O5 samples were also prepared by way of comparison. The photocatalytic activities of the synthesised catalysts were evaluated on the photodegradation of benzene, toluene and xylenes (BTX) solution under UVA and visible light. The level of nitrogen incorporated on N-doped TiO2–Nb2O5 catalyst was found to be 0.49 at%. Concentrations of BTX were analysed by gas chromatography applying the headspace technique. The N-doped TiO2–Nb2O5 catalyst calcined at 500°C led to reductions of benzene, toluene and xylenes greater than 65wt% after 150min of irradiation. The photocatalytic reactions followed the first order kinetics.