铁氮掺杂对石墨烯担载铂催化剂氧还原反应活性的影响

Effect of Fe-N doping on Oxygen Reduction Reaction Activity of Graphene-Supported Platinum Catalysts

高氧还原活性担载铂催化剂的研发是加快质子交换膜燃料电池商业化进程的主要手段之一。以石墨烯为碳源,1,10-菲啰啉为氮源,FeCl3为铁源,用浸渍法制备铁氮掺杂石墨烯(FeN-G)载体,并通过乙二醇还原法获得Pt/FeN-G催化剂,探究铁氮原子的引入对石墨烯担载铂催化剂氧还原反应(ORR)催化活性的影响。采用X射线衍射、比表面积和孔径分布测试、X射线光电子能谱等表征手段对载体及催化剂结构进行表征,使用电化学方法对载体和催化剂的ORR活性进行测试。结果表明,Pt/FeN-G催化剂的氧还原反应起始电位及半波电位分别为0.96V和0.83V,优于相同Pt担载量的商业20%Pt/C催化剂。改性石墨烯载体在热处理过程中获得更高的介孔含量,这更有利于ORR过程中生成物与反应物的传递,Pt/FeN-G催化剂中存在吡啶氮和Fe-N型氮与铂纳米颗粒的协同催化,以及铂纳米颗粒与铁氮掺杂石墨烯载体间的相互作用,是Pt/FeN-G催化剂具有优异的ORR催化活性的可能原因。

The research and development of supported platinum catalysts with high activity toward oxygen reduction reaction(ORR)is one of the effective ways to accelerate the commercialization of proton exchange membrane fuel cells.Iron and nitrogen co-doped graphene(FeN-G)was prepared by impregnation method using graphene,1,10-phenanthroline and FeCl3 as carbon,nitrogen,and iron source,respectively.Pt/FeN-G catalyst was obtained by ethylene glycol reduction method using FeN-G as support.The effect of iron and nitrogen on catalytic activity of Pt/FeN-G catalyst for ORR was investigated.The structures of the support and catalyst were characterized by X-ray diffraction,specific surface area and pore size distribution test and X-ray photoelectron spectroscopy,as well as the oxygen reduction reaction activity of Pt/FeN-G was tested by electrochemical methods.The mesopores presented in FeN-G can increase the transportation of products and reactants in ORR process.The synergistic effect of pyridine nitrogen,Fe-N-type nitrogen and platinum nanoparticles,as well as the interaction between platinum nanoparticles and Fe,N co-doped graphene can improve the ORR activity of the Pt/FeN-G catalysts.The Pt/FeN-G had better ORR activity than commercial 20%Pt/C catalyst with onset and half wave potential were 0.96V and 0.83V respectively.