SURFACE MODIFICATION OF OXIDIZED RHODIUM ELECTRODE WITH AMMONIUM ADDITIVES

Complex investigation of the processes that occur in the solution and the surface layer of oxidized rhodium during electrosynthesis of perbo rate in the presence of an ammonium additive is performed. The study i s carried out utilizing a combination of electrochemical and XPS techn iques in conjunction with quantum-chemical calculations. Possible path s for the interaction of nitrogen-containing species with the rhodium- anode surface are considered. Based on an analysis of the products of oxidation of the additive in the solution and at the electrode, sugges tions are put forth on possible techniques for surface modification an d pathways of the additive transformation. We found that it is the pro ducts of the ammonia oxidation, i.e., nitrogen-containing species, tha t interact directly with the surface. These become incorporated in the first coordination sphere of rhodium forming a strong covalent Rh-N b ond.