关键词: 钴锰复合氧化物, 共沉淀法, 氧还原催化, 金属燃料电池

Abstract: It has an important strategic significance to promote the utilization of clean energy, ensure the safety of electricity and then achieve carbon peaking and carbon neutrality goals. Therefore, we must promote the adjustment of energy structure, and develop technologies that are green, environmental protection, and low carbon energy saving. With excellent characteristics, such as high energy density, low cost, high safety, and clean and pollution-free, metal fuel cell has become a new generation of electric energy device, gained widespread traction in recent years. However, due to a lack of breakthroughs in key technologies and the high cost of cathode catalysts, metal fuel cells have not achieved large-scale application. There is great significance to developing non-precious metal catalysts, which can promote the development and promotion of metal fuel cells. In this work, carbon nanotubes, cobaltous acetate, manganese acetate, and sodium hydroxide were used as raw materials, which were much cheaper than platinum-carbon. Transition metal oxides were prepared and supported on the multi-wall carbon nanotube matrix through the method of coprecipitation, which was a spinel phase CoMn3Ox/CNTs catalyst. The XRD and oxygen reduction reaction (ORR) results indicated that increasing the pyrolysis temperature from 250℃ to 350℃ increased the crystallinity of the catalyst and the catalytic activity for oxygen reduction. The catalytic activity of CMO/CNTs-400 decreased as the particles grow a little larger. The SEM/EDS results showed that CoMn3Ox uniformly loaded on the surface of carbon nanotubes, with a particle size of nanoscale and a uniform distribution of each component element. The atomic number ratio of Co and Mn elements was close to 1:3. The current density and half-wave potential were 5.59 mA/cm2 and 0.75 V, respectively, which was obtained from ORR of CMO/CNTs-350. Furthermore, the CMO/CNTs-350 catalysts maintain good performance after macroscopic preparation. At 3 kW loaded, the aluminum air fuel cells assembled with CMO/CNTs-350 catalysts could operate at constant power for 12 h, with an average voltage of 1.14 V at the end of the test. Based on abundant and easy raw materials, a controllable production process and excellent electrochemical performance, CMO/CNTs-350 catalyst was a promising cathode for use in potential cathode catalysts for metal fuel cells.

Key words: Cobalt manganese composite oxide, Coprecipitation method, Oxygen reduction catalysis, Metal fuel cell