Physico-Chemical Characterization and Interfacial Electrochemical Properties of Nanoparticles of Anatase-TiO2 Prepared by the Sol-Gel Method

Abstract

In this work, we prepared by the sol-gel method titanium dioxide nanoparticles having a large specific area (SBET = 218 m2/g). The isotherm of N2 adsorption-desorption at 77K revealed that it concerns a mesoporous solid with a maximum pore diameter of 43 Ã…. The X-ray diffraction showed that the solid is constituted of the anatase phase. The transmission electron microscopy revealed us that the synthesized grains of TiO2 are of nanometric sizes (diameter between 8 and 20 nm) and manifest under agglomerated shape. The study of its solubility in dispersing phase, by conductometric titrations, showed that the prepared solid is totally insoluble in all the domain of the studied pH. The measured inter-facial electrochemical properties, based on the isotherms of ionic adsorption and the conductometric titrations, are: the point of zero charge found equal to 6,2±0,1, the total number of sites of surface found equal to 5,8 OH/nm2 and the nature of action of the dispersed phase on the dispersing phase which is found organizer of the structure of water. Besides, the difference of the ionization constants ï„pK is found superior to 4 for all the adsorbed ions and the constants of surface complexation are independent from the nature of the adsorbed ion.