Optimizing the Photocatalytic Activity of Nanostructured Titanium Dioxide / Carbon Nanotube Composites by Modifying the Surface Chemistry

Titanium dioxide (TIO2) is widely used as a photocatalyst. In this work, we employ sol-gel chemistry to synthesize nanostructued TIO2 microspheres. To enhance the photocatalytic activity, we incorporate carbon nanotubes into the microspheres. Furthermore, the exposed surfaces of the TIO2 and carbon nanotubes are chemically modified. The particle size and morphology are characterized with scanning electron microscopy, the nanostructure is determined with transmission electron microscopy and x-ray diffraction, and the chemical composition with FTIR spectroscopy. We demonstrated control over the mesoporosity, crystallinity, morphology and surface chemical composition. To quantify the photocatalytic activity of the TIO2 particles, we measure the photodecomposition of the Rhodamine dye under ultraviolet irradiation. A parametric study was performed to find the optimum conditions for maximum photocatalytic activity.