Electrolytic composite Co [sbnd]P [sbnd]TiO 2 layers as electrode materials for oxygen electroevolution

Abstract

Electrolytic composite layers Co P TiO 2 were obtained by electrolytic codeposition of cobalt and TiO 2 on a copper substrate from an electrolyte containing a suspension of TiO 2 (100 g dm −3). The process of electrodeposition was carried out under galvanostatic conditions, in the current density range of 17–40 mA cm −2 with a constant value of electric charge Q = 0.12 A h. For comparison, Co-P alloys were also obtained under the same conditions and comparative tests were conducted on them. The phase and chemical composition of layers were determined depending on deposition current density. Electrochemical tests were preceded by electromodification of layers aimed at obtaining an active surface layer. Investigated layers were subjected to a cyclic cathode-anode polarization in the potential range from the value of the hydrogen evolution potential to the value of the oxygen evolution potential for 3 h in 5 M KOH solution. On the surface prepared in such a way the final i-E relation was recorded for each type of layer. After such electrochemical pretreatment, all layers were tested for the process of oxygen evolution in alkaline environment. It was ascertained that incorporation of small amounts of crystalline TiO 2 in the amorphous Co-P matrix improved the rate of oxygen electroevolution on these layers.