A comparison of the influence of synthesis methods on the photocatalytic activity of nitrogen doped titania-carbon nanotube nanohybrids

Abstract

The effect of the solgel and hydrothermal synthesis methods on the physicochemical properties and photocatalytic activity of nanohybrids consisting of nitrogen-doped TiO2 supported on varying ammounts (0 – 5 wt.%) of oxidized carbon nanotubes (NTiO2–oxCNT) are compared. Hydrothermal synthesis promotes the formation of cylindrical pores independent of oxCNT content while solgel synthesis results in closed pores which transition to an open cone shape upon incorporation of oxCNTs. The point of zero charge for the nanohybrids is in the acidic range. Hydrothermally synthesized nanohybrids demonstrated high photocatalytic decolorization (up to 99.8 %) of Reactive red 120 (RR 120) than their solgel-synthesized counterparts (up to 93.1 %). A 97.4 % decolorization and 84 % TOC removal was achieved by the nanohybrid NTiO2–oxCNT 5 wt.% oxCNT (5H) at 30 ppm RR 120. The LC−OCD-OND technique demonstrates that the nanohybrid (5H) is selective for the degradation of the biopolymers and low molecular weight neutrals in real industrial textile wastewater under 150 min under visible light.