In connection with studies on the photographic properties of TiO2 the photocatalytic deposition of palladium and the electrochemical properties of TiO2 were investigated. In order to study both phenomena simultaneously the experiments were performed with thin, TiO2 layers deposited on a conducting substrate. It could be shown that the primary step is an anodic photocurrent (O2 evolution) which catalyzes the cathodic deposition of palladium under open‐circuit conditions. Various parameters such as space charge effects, film thickness, and doping were studied and are discussed in detail.

Oxidation and reduction processes of silver-silver oxide electrodes were studied, especially the influence of light excitation on these processes. The experimental results have shown that light absorption by silver (I) oxide leads to an anodic oxidation to silver (II) oxide. The electrochemical reduction of silver (II) oxide formed during illumination is considerably inhibited. A possible mechanism explaining the photoelectrochemical processes and the inhibition is discussed.

The electrochemical behavior of SnO2‐electrodes was studied. SnO2 shows typical properties of a semiconducting electrode. The oxygen evolution proceeds via the valence band whereas most redox processes occur via the conduction band. Since the potential distribution at the interface is of great importance for charge transfer processes at SnO2 it was investigated in detail. It could be shown that the doping of SnO2 and the composition of the electrolyte strongly influence the potential distribution and consequently the charge transfer processes.

It is reported on charge transfer processes between redox systems and SnO2‐electrodes. It could be shown that in most cases an electron transfer by tunneling through the space charge layer into the conduction band determines the interfacial current. The current‐potential characteristics were quantitatively interpreted by a corresponding theoretical model. The main result obtained in this paper is the possibility to obtain absolute values of the rearrangement‐energy by which the influence of polar solvents on charge transfer processes is determined. Experimental values of this energy were obtained without making essential assumptions about other parameters. The results are compared with the theory and discussed in detail.

Dye reactions at transparent electrodes were studied by spectroscopic investigations using the attenuated total reflection technique. All experiments were performed by modulating the concentration and consequently the absorption itself (potential modulation). The applicability of this method has been demonstrated by studying the distribution of monomers and dimers in adsorbed dye layers (viologene) or in the vicinity of the electrode. Measurements at higher modulation frequencies have shown that unstable semiquinones in adsorbed dye layers (methylene blue, thionine) involved in the oxidation-reduction cycle could be detected.