The Alkaline Fuel Cell Oxygen Electrode And Co-n / C Catalytic Materials

This work mainly studied Co-N/C complex catalytic material for Oxygen Reduction Reaction(ORR)and Oxygen Evolution Reaction(OER) in fuel cells,including its electro-catalytic performance,equivalent circuit and kinetic parameter.Various carbon materials for cartier of gas diffusion electrode(GDE),the thickness of the electrode and different treatments were also studied in this work to prepare GDE,which can make ORR or OER present the best electrochemical performance.At room temperature,the carbon powder without anytreament contributed limited electrocatalytic ability for ORR and OER.When the carbon powder was treated by hydrochloric acid and nitric acid,the current density of the carbon electrode in the air condition increased to 57 mA·cm^-2 at potential of-0.2 V versus an Hg/HgO reference electrode,and current density was 30 mA·cm^-2for OER.It showed that carbon black not only acted as cartier,but also its hole fabric and apparent status can affect the activity and selectivity for ORR and OER.Co-N/C complex material was prepared by adding cobalt acetate followed by heat-treatment with ammonia gas.The phase and structure of the produced material was analyzed by X-ray diffraction and cobalt nitride (Co_5.47N)was generated.At the same condition,the current density of the Co-N/C complex electrode boosted to 170 mA·cm^-2for ORR,and 80 mA·cm^-2for OER,at potential of-0.2 V and 0.6 V versus the Hg/HgO reference electrode,respectively.It is obvious that the electro-catalytic performance was improved greatly in the alkaline electrolyte.AC impedance showed that because of the generation of cobalt nitride,the impedance of oxygen reduction greatly reduced,which was in favor of oxygen reduction.