Research And Evaluation Of New Type Effective Catalyst Of Oxygen Electrode

Fuel cells and metal-air batteries have attracted a wide spread attention because of the special performances such as clean, efficient, and continuous discharge under large power. For the hydrogen-oxygen fuel cells, even though the current density has reached 2A/cm², the overpotential of the hydrogen electrode will not exceed 50 mV. And even though under the small current density, the overpotential of the oxygen electrode has reached 300～400mV. Simultaneously, the oxygen electrode is also a key factor which is used to determine the performance of the metal-air batteries.Study of the catalyst for oxygen electrode is always a significant factor which restricts the technology development of the oxygen electrode. During the process of looking for the catalyst with high efficiency and low cost for the oxygen reduction reactions, researchers not only have developed advanced manufacturing technologies of expensive metal catalyst and alloy catalyst, but also have developed a plurality of compound oxides of transition metals for oxygen reduction reactions, but all of them don't work well. For example, among the widely used catalysts, although platinum has good catalytic performance, but the cost is too high, and the cheap catalyst material of MnO₂ has a certain catalytic activity for the oxygen reduction reactions, but most MnO₂ materials are micron grade powder, and the performance is not so good.In this paper, two novel and simple making methods-liquid phase synthesis and solid phase hot pressing method are used to make the manganese compound oxide catalyst for oxygen electrode catalyst, and XRD is used to characterize the crystalline structure of the catalyst materials made in this subject, and testing methods such as open circuit voltage-time, linear CV scanning, steady polarization, CV and EIS are made use of to study the catalytic performance of the catalyst materials in the acidic, alkaline, neutral and micro acidic electrolyte solutions. And the study result of the subject is compared with the foreign prior research results to investigate the application prospect of the catalyst materials.The research results of the subject shows that: the main components of the catalyst materials made in two methods are Mn3O4, and according to analyzing, there may be other manganese oxides in the catalyst materials under different making methods, wherein the catalyst made in liquid phase synthesis has good catalytic activity in acidic electrolyte solution, and appears high research value; and the catalyst materials made in solid phase hot pressing method has wonderful catalytic activity in alkaline electrolyte solution, even far exceeds the catalytic activity of the prior catalyst research results; and the catalyst material made in solid phase hot pressing method has higher catalytic activity in the alkaline medium than the catalytic activity in other medium, which shows that the mechanisms of catalytic oxygen reduction reaction in the alkaline electrolyte solution and other electrolyte solutions are different.In a word, the catalyst materials made in the subject appears good developing prospect, and has high research value, and the performance of the catalyst materials can be improved further in the research directions of optimization of the manufacturing technology and doping modification of the materials.