Preparation And Electrochemical Performance Of Co₃O₄-Based Electrocatalytic Materials For Oxygen Evolution Reaction

The oxygen evolution reaction is wildly used plays a in the renewable-energy technologies including fuel cells and water splitting. OER catalysts have been wildly studied to solve the problem of high overpotential in the process of industrialization. Currently, precious metals and oxides (e.g. Ru、Ir、RuO2、IrO2) have a good catalytic activity, the high cost and fewer reserves are the reason why precious metals and oxides have been gradually replaced by transition metals and oxides. In this work, Co3O4-based catalysts have designed to improve the poor catalytic activity and stability of the traditional transition metal oxides by using support materials and Fe solute.Firstly, the microscopic morphology of Co3O4 can be controlled through a hydrothermal synthesis method, including nanoparticles, nanorods, nanocubes, nanosheets and nanowires catalysts. The chemical and physical properties of different morphology of catalyst analysis results show that the microstructure of catalysts has a great influence on the catalytic activity. The nanoparticles catalyst with a diameter of 4-7 nm has the best catalytic activity. The potential is 0.690 V (vs.SCE) to achieve a current density of 10 mA·cm-2.Secondly, this study used highly graphitic carbon black (GCB) as the support materials to prepare Co3O4/GCB catalysts which improved the conductive ability and surface area of the catalysts. Co3O4 nanoparticles with average sizes of 5 nm were uniformly loaded on GCB. Co3O4/GCB catalysts have larger specific surface area and good conductive ability, which could help to have a better OER catalytic activity than Co3O4 catalysts from the results of electrochemical tests. The potential is 0.670 V (vs.SCE) to achieve a current density of 10 mA·cm-2 and in the stability test, the current density lose of Co3O4 catalysts and Co3O4/GCB catalysts is individually 20% and 10%.Finally, the FexCoyO4/GCB catalysts have been prepared by using the solute of iron, which result in a further improves of the catalytic performance for OER. The potential of the FexCoyO4/GCB catalysts is 0.637 V to achieve a current density of 10 mA·cm-2, which is 33 mV smaller than the overpotential of the Co3O4/GCB catalysts. The FexCoyO4/GCB catalysts also suffered nearly no current decrease in the stability tests of OER cycling in 1 M KOH electrolyte. The Co3O4-based catalytic materials show a good potential in the development of new energy technology because of their excellent catalytic ability for OER.