EXAMINATION OF THE CORROSION SUPPRESSION MECHANISM ON N-TITANIUM DIOXIDE PHOTOANODES

It has been postulated that corrosion of TiO2 photoanodes and its suppression are correlated with the presence of sulfate radicals. This idea was investigated by measuring the effects of light intensity, Co2+ concentration, and H2SO4 concentration on corrosion rate. Results showed that corrosion rate was proportional to (light intensity)1/2, that an increase in Co2+ concentration decreased corrosion rate in 0.5M H2SO4, and that with an increase in H2SO4 concentration, corrosion rate increased up to 0.5M acid and then decreased. These results are consistent with the proposed suppression mechanism and support the idea that high energy reactions can be kinetically favored over lower energy reactions because they involve only a single electron transfer between the electrode and the reacting electrolytic species. © 1979, The Electrochemical Society, Inc. All rights reserved.