INFLUENCE OF LOW-TEMPERATURE AND ELECTRICAL-FIELD STRENGTH ON OXYGEN EVOLUTION (PHOTO)CATALYSIS WITH N-RUS2 ELECTRODES

The anodic oxygen evolution in dark and under illumination on three differently degenerate semiconducting RuS2 crystals was investigated in aqueous perchloric acid in the temperature range 300-180 K. In the liquid state (T > 228 K), in darkness, the preexponential factor and the activation energy increase according to the degeneracy of the crystals. The same trend was also observed in the frozen state (T < 228 K). In comparison to the liquid state, the preexponential factor and the activation energy were 4 orders of magnitude and a factor of 2 lower, respectively, in the frozen state. A model emphasizing the influence of the electric field in the Helmholtz layer on photoelectrocatalysis is proposed to explain the behavior of these differently degenerate semiconductors.