Photoelectrochemical Production of Atomic Hydrogen at Tungsten Bronze/Aqueous Solution Interface

The cathodic photoeffect on hydrogenated sodium tungsten bronzes was studied in acid solutions under potentiostatic conditions. Solute effect proved the accompanying chemical reactions in the liquid phase to be brought about by hydrogen atoms. Kinetic analysis of the photocurrent showed that photoproduction and second‐order recombination of the charge carriers in the solid are followed by reversible reduction of H + at the interface. Finally H‐atoms react with solutes like , , Fe 3+ , , or tetranitromethane. The kinetics of charge carrier formation and of chemical reactions seem to be only weakly coupled, and the entire process can be described in terms of homogeneous kinetics showing diffusion and migration to be kinetically unimportant.