Graphene Prepared By Higee And Its Application Research In The ORR

Fuel cell has been given much attention because of its high energy conversion rate and little pollution to the environment. However, its commercialization is hampered because of its high production cost and poor durability. Therefore, finding a new type of non-noble metal to take place the precious metal platinum catalyst is the key to achieve the long-term development of fuel cell and its industrialization.Graphene has the structure of special two-dimensional mesh. The special structure make it have wonderful properties, such as electrical conductivity and high specific surface area. It can improve the ORR activity of graphene when nitrogen is doped in the graphene lattice structure.In this paper, the nitrogen doped graphene samples were prepared by using hydrothermal reaction according to the different ratio of graphene oxide prepared by high gravity and urea under the condition of at 180? for 20h, both of which was used as carbon source and nitrogen source separately. The results show that,1:400 is a better ratio of graphene oxide and urea when preparing nitrogen doped graphene. Hydrothermal reaction can achieve the reduction of oxygen and the doped of nitrogen at the same time, and that makes it a green and effective technology. Compared with the undoped samples, the initial reduction voltage of the nitrogen doped samples offset to the right for 45mV. When the voltage is-1.0V, the electron transfer number is 4.1, indicating that it is a good ORR activity. And the reason that the performance of ORR becomes better is believed to be the function of pyridinic nitrogen.In order to compare with the performance of the nitrogen doped graphene prepared by high gravity, graphene oxide that prepared by traditional ultrasonic method was also used to prepare nitrogen doped graphene under the same condition. The results show that the initial reduction voltage of the electrode modified by the better nitrogen doped graphene offset to the right of undoped graphene samples for 69mV. Under the same condition, the best nitrogen content of utrasonic is less than that of high gravity. The reason for this difference is that the surface area of graphene obtained by rotating packed bed is larger, the number of layers is less, and these make more nitrogen can be doped, so the voltage range of graphene prepared by rotating packed bed is wider. It is proved that preparation of graphene by using high gravity in the fuel cell catalyst has good application prospects.