Bifunctional Oxygen Electrode And Its Electrochemical Properties

Oxygen electrode, regardless oxygen evolution reaction (OER) or oxygen reduction reaction (ORR), is an important subject in water lectrolysis, fuel cells and metal hydride-air secondary cell. However, application of the oxygen electrode is mostly restricted by its poor catalytic capability.In this paper, firstly, the Co-based catalyst for OER is prepared on Ti substrate by electrodeposition method with methanol, ethanol and isopropanol as additives. The effects of additives on the morphologies and electrocatalytic activity of the Co-based catalyst are studied. The morphology, crystal structure and composition of catalysts are characterized by XRD, SEM and IR, respectively. The square wave potential technique is used to assess the real surface area. It is found that additives have dramatic effects on the morphologies of catalysts. The flower-like nanostructures, which can be obtained through adding different monohydric alcohols, are conducive to increase the specific surface area. Additionally, a survey on electrochemical characteristics of electrodes is further explored by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and single potential step chronoamperometry (CA) in the alkaline and neutral electrolyte solutions. The results indicate that the introduction of additives can enhance OER to a certain extent. The best catalytical activity for OER is obtained on the Co-based catalyst (yc-Co) with ethanol, which is prepared at 25℃, 12 C of deposition charge, and 350 mA cm-2 of deposition current density.Secondly, the yc-Co-Pt complex electrode is prepared by two-step electrodeposition method, and used as bifunctional oxygen electrodes in the alkaline and neutral medium. The results show that: The yc-Co-Pt bi-component electrocatalyst, which combines the advantages of the yc-Co catalyst and Pt catalyst, exhibits good activity for OER and ORR. It can be speculated that ORR and OER take place at the Pt and yc-Co electrocatalyst, respectively. The yc-Co-Pt complex electrode has good overall performance as bifunctional oxygen electrode.