The kinetics of water photo-dissociation assisted by visible light was the main topic of this work. The Rh doped SrTiO₃ semiconductor was employed as photo-excitable material. It can absorb visible light and therefore transform solar energy into useful chemical fuels. In this manuscript, a wide bibliographic overview is provided in the 1st Chapter, covering a description of the characterization methods and current models for photoelectrochemical kinetics. The 2nd Chapter is devoted to the description of the materials and methods. The 3rd Chapter deals with the full photoelectrochemical kinetic characterization of water splitting with Rh:SrTiO₃ photoelectrodes, surface-modified by addition of a model clathrochelate or with metallic Cu or Pt. In the 4th Chapter, a theoretical study of the mechanism of hydrogen evolution catalyzed by a model clathrochelate is provided. During the discussion, the EXAFS spectrum of the organometallic complex was thoroughly analyzed and modelled, and the relevant protonated intermediates involved in the mechanism were identified. The 5th Chapter deals with the photoelectrochemical dynamics of illuminated Rh:SrTiO₃ -based photo-electrodes, characterized by the light-modulated photovoltage technique. Unusual results were obtained and are reported in this thesis for the first time. This unexpected dynamic behavior has been modelled by a set of classical differential equations usually used to describe such photo-processes.