Conventional photoelectrochemical and photovoltaic theory predicts a light intensity threshold for sustaining the net electrolysis of water using semiconductor electrodes, but a stochastic charge-transfer formalism for photoelectrolysis reactions does not predict such threshold behavior. This work examines the theoretical and experimental aspects of light-assisted water electrolysis using n-type SrTiO3/H2O interfaces. A theoretical framework, based upon simple chemical kinetic considerations, has been formulated to describe the behavior of such photoelectrosynthetic cells. Experiments conducted on the n-SrTiO3/5.0 M NaOH(aq)/Pt photoelectrosynthetic cell have revealed a threshold in the short-circuit electrolysis current at 5 × 10-5 W/cm2 of 325-nm illumination. Additional theory and experiments have provided insight into relationships between two-electrode regenerative photoelectrochemical cells, two-electrode photoelectrosynthetic cells, and three-electrode potentiostatic cells. These experiments and theory indicate that a conventional chemical kinetic treatment of interfacial electron-transfer rates appears to be sufficient to describe the photoelectrochemical behavior of SrTiO3 and TiO2/aqueous junctions.
|Number of pages||9|
|Journal||Journal of Physical Chemistry|
|Publication status||Published - 1992|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry