Photo-electrochemical reactions of pigmentary titanium dioxide

Abstract

The photo-electrochemical reactions of pigmentary titanium dioxide have been investigated using electrochemical cells having a platinum electrode coated with the oxide. E.m.f. and current measurements show that the oxide behaves as an n-type semiconductor. The e.m.f. increases linearly as the logarithm of the light intensity is increased. Increase in temperature above ambient leads to a decrease in the e.m.f. Photo-currents were found to depend on the extent of anodic biassing and on the square root of the light intensity. Increasing the temperature above ambient leads to increased photo-currents. The results are discussed in terms of the band-gap theory for semiconductors.