Carbon xerogel/TiO₂ composites

ABSTRACT

Carbon xerogels (CXs) are materials with three-dimensional structure of nano-sized balls and interconnected pores. CX have been widely applied as metal support for use in catalysis. The main advantage of these materials is that their physical and chemical properties can be adapted for each catalytic requirements. In this work, CX/TiO₂ compounds have been synthesized in a single step, which consisted in the polymerization sol-gel/condensation of resorcinol and formaldehyde solution, with simultaneous addition of TiO₂ nanoparticles or Ti(IV), followed by drying and heat treatment. The composites were characterized by thermogravimetric analysis (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and adsorption isotherms of nitrogen (N₂) to determination of surface area (BET) and pore volume (VP). The results showed the presence of a mixture of anatase and rutile phases in the composites. Although SEM images it was verified higher uniformity in the distribution of TiO₂ particles in CX support. The photocatalytic properties were investigated for the degradation of methylene blue (AM). The kinetics of the photocatalytic process was determined as the pseudo first-order model. There was a synergistic effect between the solids, with an increase of photocatalytic activity in composite CX/TiO₂, compared to TiO₂.

Keywords
carbon xerogels; photocatalysis; titanium dioxide