Investigation of photocatalytic performance of TiO2 network and fiber geometries

In typical photocatalytic processes slurry reactors are used in which catalyst particles have to be separated from the solution after the process ends which means much higher time and costs. Hence, immobilizing process is carried out on the catalyst to overcome this problem. In this work, fiber and network geometries were produced by particle precipitation on substrates. The obtained structures were characterized by XRD, SEM, and Brunauer-Emmett-Teller analyses. Photocatalytic performance of the samples was investigated by methyl orange degradation and also by hydrogen generation from water/methanol splitting. From the SEM images, the size range of the TiO2 particles in the network geometries were 20-60nm. The nanoparticles had covered the surface of the substrate uniformly. Removal of the cellulose substrate by heat treatment yielded hollow TiO2 fibers with diameters of 0.5-1m and lengths of 30m. The rate constant of the dye degradation reaction using powder catalyst was 0.0118min(-1). However, the rate constants for fiber and network geometries were 0.0057 and 0.0083min(-1) respectively. The amount of hydrogen generated from different catalysts was determined to be in the following order: powdery>network>fiber.