Induced surface photovoltage in TiO$_2$ sol-gel nanoparticles

TiO$_2$ nanoparticles synthesized by the sol-gel method and modified by annealing in air and hydrogen atmospheres were studied by surface photovoltage spectroscopy (SPS). SPS measurements showed that the modified in air TiO$_2$ nanoparticles have a more intense signal than those treated in hydrogen. A linear correlation was found between the SPS and the diffuse reflectance spectra of the samples.