THE REDUCTION OF HYDROGEN-PEROXIDE AT SILICON IN WEAK ALKALINE-SOLUTIONS

The reduction of H2O2 at silicon was studied at 70°C in solutions with a pH of 12.0. Voltammograms showed that this reaction is very sensitive to the state of the silicon surface. At passivated electrodes the reduction at n-type material proceeds in the dark, while at p-type electrodes illumination is necessary and current doubling is observed. In the active state silicon dissolves chemically in the aqueous solution and reduction of H2O2 takes place in the dark both at n- and p-type material. A mechanism is proposed, in which charge transfer between H2O2 and intermediates of the dissolution reaction takes place. The chemical dissolution resulted in an extreme change of the surface morphology, exposing various crystallographic facets at the surface. © 1990.