LED visible-light activated mesoporous TiO2: A better understanding about carbon role in the photocatalytic performance of solid

Abstract

Carbon and iron co-doped mesoporous titanium dioxide nanoparticles were successfully synthesized through an environmentally friendly methodology. The samples were characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DR), N2 adsorption/desorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Significant advances about the nature of carbon species responsible of photosensibility of solids, distinguishing furthermore between environmental surface carbon and the carbon that truly forming part of the oxide network, are presented. In order to avoid confusing results that frequently arise from conventional XPS analysis, pickling studies were carried out measuring depth XPS profiles. Effect of a calcination treatment and the co-doping with Fe was studied in terms of the response of solids to visible light coming from LED modules for the Ibuprofen degradation. The highest degradation of the drug (about 90 %) was reached in 5 h of reaction using photocatalyst co-doped with Fe/C and treated at 200 °C. The generation of new electronic states narrowing the TiO2 band gap due presence of carbon and iron in interstitial and substitutional sites of network is proposed to account for this behavior.