| Abstract [eng] |
Hydrogen produced by water electrolysis is a viable clean alternative to fossil fuels. The main limiting stage of electrolysis is the release of oxygen and the use of the most efficient platinum group catalysts is limited by their cost. As an alternative to expensive catalysts, universally available transition metal oxide compounds of subgroup 3d are promising. Graphite felt with a high active surface is a suitable basis for chemical and electrochemical modification in the production of composite electrodes. In this project, graphite felt was modified with individual Fe, Ni and Co oxides and their mixtures. The modification was performed using impregnation and heating methods with Co(II), Ni(II) and Fe(III) acetate solutions. The weight gain in most samples after three modification cycles was about 50%. Scanning electron microscopy showed that the graphite felt filaments were coated with the appropriate metal oxides after modification, except in the iron oxide-modified specimen, where the metal oxide filled the space between the filaments. Linear sweep voltammetry showed that the modification increased the anodic current of graphite felt by about 6 times at 1.5 V and by about 3 times at 2 V. The cobalt oxide-modified electrode had the highest current density at low potentials, but when the potential rose above 1.4 V, the cobalt oxide-iron oxide-modified electrode had a current density that reached 77 mA/cm2 at 2 V. All electrodes had good stability and after removing the electrodes from the electrolyte, drying them and repeating the tests after a few days similar results are obtained. |
