Nitrogen Doped Porous Carbons Loaded With Platinum Particles And Their Electrocatalytic Performance

Polymer electrolyte membrane fuel cell (PEMFC) is an energy conversion deviceof a high efficiency and environmental friendness, which could start-up in short time.It can be used widely in cell phones, computers, laptops cars, air crafts, and fixedpower stations, and so on. However, one of biggest drawbacks limitting theperformance of PEMFC is its high cost due to using a large amount of precious metalplatinum as catalyst for oxygen reduction reaction. Therefore, to explore the catalystswith high efficiency, low Pt loading and high stability is an important task indeveloping PEMFC. In this work, the catalysts of platinum loaded N-doped porouscarbon have been prepared by using the method of chemical impregnation liquidreduction methold. The effects of texture and structural configuration ofnitrogen-doped porous carbon on deposition configuration and distribution of loadedcatalysts, as well as electro-catalytic properties were studied.Polypyrrole/ordered microporous carbon composite and polypyrrole/activecarbon composite were prepared and then which were carbonized at700℃or900℃to prepare nitrogen doped porous carbons (NPCs). Pore structure and BET analysesshow that the nitrogen-doped ordered microporous carbon(NOMC) mainly consists ofmespores, but the nitrogen-doped activated carbon(NAC) mainly consists of withmicropores. Nitrogen-doped porous carbons prepared by carbonizing the compositesat the temperature of900℃exhibit the higher specific surface area (SSA) but thelower amount of nitrogen doping amount. However, the samples prepared at thetemperature of700℃have the lower SSA but the higher nitrogen amount. By usingthe NCPs above as the supports of catalysts, Pt loaded NCPs were prepared. XRD andTEM analyses show that the Pt particles are distributed more uniformly as smallersize on NCPs prepared at the temperature of900℃. Electrochemical analyses on thecatalysts show that the oxygen reduction activity and stability of catalysts can beenhanced when NPCs are used as supports. Among them, the catalysts supported onthe NCPs prepared at temperature of900℃have the better oxygen reduction activity.Furthermore, compared to the Pt-NOMC900, the Pt-NAC900exhibits the higheractivity and stability for oxygen reduction due to that the higher SSA and nitrogendoping amount of NAC can supply more active area for Pt deposition and enhance theadhesion between Pt and NAC.