Characterization of Chemically Modified TiO 2 Synthesized via Sustainable Superoxidation of Ti

Enabling economic development while promoting acarbon neutral society requires management of natural resources andof energetic costs of technological processes. The quest for novel,renewable energy materials urges the use of earth-abundant resources,green synthetic processes with non-hazardous chemicals, whilemaintaining the desired functional properties. Here, we propose anoptimized process for the sustainable low temperature synthesis ofchemically modified TiO2with enhanced visible absorption andimproved electrical conductivity. The optimized synthetic procedureconsists in oxidizing a titanium foil in hydrogen peroxide at 80 degrees C for24 h. These reaction temperatures and duration are sufficient to yielda uniform nanostructure with high porosity. Complementarycharacterization techniques confirm the formation of an amorphousTiO2phase accompanied by the formation of a surface layer withhydroxyl and peroxo groups. This surface layer could introduce mid gap defect states and improve the absorption properties of thismaterial in the visible range. Accordingly, the photocatalytic property of the modified TiO2show improved activity towarddegradation of Rhodamine B dye with respect to stoichiometric TiO2. Electrochemical measurements, including Mott-Schottkyanalysis and impedance spectroscopy, show that H2O2-treated Ti foil exhibits an improved charge transfer kinetics and shortercharge transfer time (up to ten times lower) with respect to stoichiometric TiO2. Overall, the results presented in this work supportthe application of green synthetic routes for the fabrication of functional materials for renewable energy processes.