快速微波法制备掺氮石墨烯用于碱性氧还原电催化剂(英文)

Rapid synthesis of nitrogen-doped graphene by microwave heating for oxygen reduction reactions in alkaline electrolyte

采用微波法在氨气气氛下快速加热石墨烯(G)制备了含氮量在4.05 wt%–5.47 wt%的掺氮石墨烯(NG).将上述的掺氮石墨烯用作碱性电解质条件下的氧还原电催化剂,起始还原电势为0.17 V(vs SHE),接近商用碳载铂催化剂的0.21 V(vs SHE).采用透射电子显微镜、拉曼光谱和X射线光电子能谱研究了掺氮石墨烯的形貌、结构和掺杂氮原子的键合方式.结果发现,掺氮石墨烯的氧还原起始电位随着石墨氮原子含量的提高而上升,说明石墨类型的氮含量是影响其氧还原催化活性的关键因素.实验结果表明,微波法快速制备的掺氮石墨烯在碱性条件下表现出较高的氧还原催化活性,具有作为碱性燃料电池阴极催化剂的潜力.

Nitrogen-doped graphene （NG） with a nitrogen content from 4.05 wt% to 5.47 wt% was rapidly prepared via microwave heating of graphene under NH3 flow. The as-synthesized NG samples were then used as electrocatalysts in the oxygen reduction reaction （ORR） in alkaline solution. The NG samples showed excellent ORR catalytic activity with an onset potential of 0.17 V, which is compa-rable to that of commercial Pt/C electrocatalyst （0.21 V）. The structure, composition, and nitrogen species of the NG samples were examined by transmission electron microscopy, Raman spectros-copy, elemental analysis and X-ray photoelectron spectroscopy. The onset potential increases with the content of graphite nitrogen in the NG samples, indicating that graphite nitrogen might be the main factor controlling the performance of the NG samples in the ORR. The results showed that NG prepared by rapid microwave heating is a promising ORR catalyst for fuel cells.