氮掺杂石墨烯的制备及其氧还原电催化性能

以三聚氰胺和氧化石墨烯(GO)为原料,经物理研磨和高温热解得到氮掺杂石墨烯(三聚氰胺-NG).扫描电子显微镜(SEM)测量显示,所制备的三聚氰胺-NG厚度和表面褶皱较掺杂前略有增加.X射线光电子能谱(XPS)表明,在三聚氰胺-NG中氮元素以吡咯N、吡啶N和石墨N 3种形式掺杂在石墨烯中,它们的比例分别是14.5%、24.5%和61.0%.同时运用循环伏安法(CV)和旋转圆盘电极技术(RDE)测试了三聚氰胺-NG在碱性介质中的氧还原电催化活性.结果表明,与商业石墨烯和由聚吡咯为氮源制备的氮掺杂石墨烯(ppy-NG)相比,三聚氰胺-NG具有较高的电催化活性和较正的氧还原起始电位(-0.09V),并且电催化还原氧气时主要为4电子反应.由于其较高的氧还原性能和较低的成本,三聚氰胺-NG在碱性燃料电池阴极电催化剂中有良好的应用前景.

Synthesis of Nitrogen-doped Graphene and Its Electrocatalytic Performance Toward Oxygen Reduction Reaction

A nitrogen-doped graphene with high electrocatalytic abilities toward oxygen reduction reaction(ORR)was prepared via physical mixture of graphene oxide and melamine and one-step pyrolysis in N2.According to the scanning electron microscopy(SEM)measurements,the nitrogen-doped graphene prepared from melamine has higher thickness and overlap.Xray photoelectron spectroscopy(XPS)shows that nitrogen is successfully doped in graphene with the formation of pyrrole-like N,pyridine-like and graphitice-like N,the content ratios of different nitrogen were calculated to be 14.5 %(at),24.5%(at)and 61.0%(at),respectively.According to cyclic voltammogram(CV)and rotating disk electrode(RDE)measurement,the as-prepared nitrogen-doped graphene exhibit higher electrocatalytie activity with an onset potential of-0.1Vin an alkaline electrolyte in comparison with commercial graphene and polypyrrole-doped grapheme(ppy-NG),and the overall electron transfer number in the catalyzed ORR was found to be 4.Due to high electrocatalytie activity for ORR and low costs,the nitrogendoped graphene prepared from melamine would be a potential candidate as an cathode electrocatalyst in alkaline fuel cell.