Nano-engineered materials for H2 production by water photo-electrolysis

Nano-engineered materials based on TiO2/Ti are proposed as suitable photo-catalysts in studies of novel processes for energy production by renewable and non-polluting sources. The samples, prepared by anodic oxidation, were tested in a laboratory scale photo-reactor, designed on purpose to maximize the catalytic performance of thin substrates in H2 evolution by water splitting. The voltage applied during the anodization influences the mean dimension of the nanostructures, their wall thickness and degree of packing, and also their photo-catalytic performance. The surface characterization (made by FESEM, TEM, GAXRD, UV-Vis diffuse reflectance and current-time transients during the anodization process) revealed amorphous titania in the nano-structured thin films, the anatase phase appearing only after annealing up to 500°C. Photo-catalytic results showed that H2 production strongly depends on the quantity of titania anodized on the Ti substrate.