TiO2–CeO2 composite coatings for photocatalytic degradation of chloropesticide and organic dye

Spray pyrolysis was used to deposit CeO 2 –TiO 2 coatings on stainless steel substrates. The addition of CeO 2 to TiO 2 changes morphology of the coatings, causing the surface to become laced and some CeO 2 ions are incorporated into TiO 2 crystal lattice. Part of CeO 2 is highly dispersed on the surface of TiO 2 . The XPS showed the simultaneous existence of Ce 4+ and Ce 3+ on coating surface. As the CeO 2 content in composites increases from 0.5 to 20%, the band gap decreases from 3.16 to 2.88 eV, respectively. The photoactivities in the degradation of methyl orange and lindane were significantly influenced by the content of Ce in composite. For methyl orange photodegradation, the highest activity had coating with CeO 2 content of 2 wt%. In contrast, the activity of coatings in lindane photodegradation gradually decreases as the CeO 2 content increases. However, efficiency of CeO 2 –TiO 2 coatings remained satisfactory for application in process of lindane degradation. Lindane conversion at 6 h of irradiation is in the range from 88% for pure TiO 2 to 60% for CeO 2 –TiO 2 coating with CeO 2 content of 20 wt%. Photodegradation of lindane was enhanced on pure TiO 2 sites, while methyl orange degradation is highest on composite CeO 2 /TiO 2 species with CeO 2 content of 2 wt%.