Synthesis of three-dimensional carbon felt supported TiO2 monoliths for photocatalytic degradation of methyl orange

Abstract

Three-dimensional carbon felt supported TiO2 (TiO2@CF) monoliths were synthesized via a solvothermal process. The structural properties of TiO2@CF were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N2 adsorption–desorption, Raman and contact angle tests. The as-prepared TiO2@CF monoliths exhibited a large surface area, hydrophilic surface as well as a well-defined three dimensional structure. Using methyl orange as a model pollutant, the photocatalytic activity of TiO2@CF monolith was studied. The effects of substrate concentrations, pHs of pollutant solutions and H2O2 concentrations in the degradation of methyl orange were examined. It was revealed that a low pollutant concentration, adequate H2O2 concentration and acidic environment facilitated the degradation of methyl orange. To explore the mechanism, controlled experiments were conducted by adding three scavengers including isopropanol, p-benzoquinone and ethylenediaminetetraacetic acid disodium salt. Mechanistic studies suggested that in the presence of H2O2, hydroxyl radicals played a dominant role in the degradation of methyl orange while the photo-induced holes were mainly responsible in the absence of H2O2. The TiO2@CF monolith catalysts could be easily regenerated via combustion and showed excellent recyclability.