NEW POROUS IRON ELECTRODE FOR HYDROGEN EVOLUTION - PRODUCTION AND PROPERTIES

A new method of fabrication of porous iron electrode is presented. In due of growing interest for hydrogen production by use of electrochemical technology. the extensively research of new cheaper electrode material currently are lead. At present production of industrial porous metal electrodes is mainly based on fabrication nickel HSE (high) surface area) electrodes by sintering, of nickel powder in oxygen less atmosphere or etching of Rancy alloy to Ni-Rancy electrodes. We proposed to use cheaper porous iron electrodes produced from iron powder instead of the expansive nickel ones. An inexpensive method of production is based on Successive oxidation and reduction of the iron powder bed. This work deals with kinetics of oxidation at 400 and 600 degrees C of iron powder bed in air and water vapor. Thermal effect during oxidation process was determined by DTA/TG analysis. Reduction process of porous oxidized precursor in hydrogen at 600 degrees C was also Studied. The surface morphology of the porous oxidized precursor as well as the received porous metallic iron Structure were examined by SEM. The chemical composition was determined by SEM/EDX and XRD analysis. The optimal condition (i.e. time, temperature) for fabrication process of iron porous electrode with highest Specific surface area and open porosity was appointed. The electrochemical properties of porous iron electrodes (obtained in different conditions of oxidation process) were examined by potentiodynamic measurement. The current-potential dependence was obtained in 1M KOH at 70 degrees C vs. Hg-HgO reference electrode i.e. in conditions corresponding with industrial process of hydrogen production. Hydrogen evolution reaction on iron in conditions mentioned above is considering with the Volmer-Heyrovsky-Ttfel kinetic mechanisms. For porous electrode and hulk sample iron and nickel electrodes the E-100 potential corresponding for evolution of hydrogen with current density 1000 A/m(2) was determined. E-100 potential is assuming 12 values from -1.24 to -1.32 V (depends of sample history) for porous iron electrodes. This potential for bulk iron electrode (-2.96V) and nickel (-1.50V) is significantly higher.