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Hybrid structured photocatalysts based on sepiolite, an adsorbent, and TiO2 were prepared by extrusion of ceramic dough and conformed as plates. The influence of the photocatalyst configuration was studied either by including TiO2 in the extrusion process (incorporated materials) or by coating the sepiolite plates with a TiO2 film (coated materials). The influence of the OH- surface concentration in the photocatalytic performance was studied by treating the ceramic plates at different temperatures. The samples were characterized by N2 adsorption-desorption, MIP, SEM, XRD, and UV-vis-NIR spectroscopy and tested in the photocatalytic degradation of trichloroethylene (TCE) as a target VOC molecule. Most of the catalysts presented high photoactivity, but considerable differences were observed when the CO2 selectivity was analyzed. The results demonstrate that there is a significant effect of the catalyst configuration on the selectivity of the process. An intimate contact between the sepiolite fibers and TiO2 particles for incorporated materials with a corncob-like structure favored the migration of nondesirable reaction products such as COCl2 and dichloroacetyl chloride (DCAC) to the adsorbent, reacting with OH- groups of the adsorbent and favoring the TCE mimeralization.

Porous TiO 2-anatase films were prepared by sol-gel route showing higher photocatalytic activity in degradation of trichloroethylene (TCE) in air compared to dense titania films. Thus, titania sols were synthesized with and without a pore generating agent, polyethylene glicol (PEG), to evaluate the effect of porosity in the photocatalytic activity of the coatings. The films were deposited by dipping and sintered at different temperature and time. The characterisation was performed by profilometry, Fourier Transform Infrared Spectroscopy (FTIR), Grazing X-ray Difraction (GXRD) and Field Emision Scan Electron Microscopy (FE-SEM), observing that anatase phase is obtained at temperatures as low as 350 ºC. The maximum specific surface area (S s = 43 m 2 /gr) was obtained for coatings prepared from TiO 2 sol with PEG and sintered at 400 ºC. Porous TiO 2-anatase films present trichloroethylene (TCE) conversion around twenty percent higher than that of dense films. Porous volume, surface area and thickness of the coating play a key role in the photocatalytic activity. On the other side, variation in particle size seems not to be a critical parameter in the studied range.

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