Sol-gel TiO2 was first prepared under basic conditions using TTIP as precursor. In a typical synthesis, 17.8 g of TTIP was first added to a 40 mL absolute ethanol solution at room temperature, before a similar volume of water was added dropwise to the solution. After rectification of the pH to 9 by adding few drops of concentrated NH3(aq.), the solution was left under agitation at 40°C until a dry paste was obtained. The resulting powder was dried at 100°C