Preparation and Characterization of Carbon Xerogel Based Composites for Electrochemical Sensing and Photocatalytic Degradation.

In order to obtain a multifunctional nanocomposite material-for electrochemical sensors and photocatalytic applications, structures based on Bi, Fe and TiO₂ were grown inside carbon xerogel supports (BiFeCX and BiFeCX-TiO₂). First, a wet polymer containing Bi and Fe salts was obtained by following a modified resorcinol-formaldehyde based sol-gel route, followed by drying in ambient conditions, and pyrolysis under inert atmosphere. Then, through TiCl₄ hydrolysis, TiO₂ nanoparticles were deposited on the BiFeCX xerogel leading to BiFeCX-TiO₂. The morphological and structural characterization of the investigated nanocomposites consisted in X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and N₂ adsorption measurements, revealing porous carbon structures with embedded nanoparticles and the particularities driven by the pyrolysis and TiCl₄ treatment. The new modified electrodes based on BiFeCX or BiFeCX-TiO₂ nanocomposite materials, kept in a chitosan matrix (Chi) and deposited on a glassy carbon (GC) electrode surface (GC/Chi-BiFeCX or GC/Chi-BiFeCX-TiO₂), were obtained and investigated for Pb(II) voltammetric detection and H₂O₂ amperometric detection. Moreover, the BiFeCX-TiO₂ nanocomposite was tested for the photocatalytic degradation of methyl orange. The great potential of BiFeCX nanocomposite material for developing electrochemical sensors, or BiFeCX-TiO₂ for sensors application and photocatalytic application was demonstrated.