微波溶剂热法制备掺氮石墨烯用于碱性氧还原反应

采用微波处理氧化石墨烯(GO)与乙二醇(EG)、乙二胺(ED)混合液的方法制备氮掺杂石墨烯(NG),使用旋转圆盘电极对NG催化氧还原在碱性溶液中反应进行研究,并考察了不同微波辐射时间、ED与EG之比对反应性能的影响。采用X射线衍射仪(XRD)、透射电子显微镜(TEM)、拉曼光谱(Raman)和傅里叶变换红外光谱(FT-IR)研究了NG催化剂的结构与性质。相比于未掺氮的石墨烯样品,NG表现出更正的起始电位和接近四电子的转移过程。NG中掺杂氮原子的键合方式通过XPS进行表征,结果表明起始电位的高低取决于石墨氮含量。此外,所有表征结果表明总氮含量与氧还原反应性能没有直接关系。

Nitrogen-doped Graphene by Microwave Solvothermal for Oxygen Reduction Reactions in Alkaline Electrolyte

Nitrogen-doped graphene (NG) catalyst on the oxygen reduction reaction (ORR) has been investigated in alkaline solution using the rotating disk electrode (RDE) method. Here, we reported a facile NG catalyst via a convenient and simple method of microwave solvothermal from graphite oxide (GO) in the mixture solution of ethylene glycol (EG) and ethylene diamine (ED). The effect of microwave irradiation time and the ratio of EG and ED on the performance of the catalyst were investigated. The structure and property of NG catalysts were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Raman spectroscopy, and Fourier transform infrared spectra (FT-IR). Most importantly, the as-synthesized NG catalyst exhibited a positive onset potential (E_ORR) and nearly four electron transfer process, which is better than non-N-graphene. Furthermore, the role of various nitrogen states in NG catalysts were investigated by X-ray spectroscopy (XPS), and the results showed that the content of graphite-N components determined the E_ORR. Besides, comprehensive characterizations revealed that NG catalyst in ORR process had no direct relationships with the content of total N.