Simultaneous Nitrogen Doping and Reduction of Graphene Oxide
Simultaneous Nitrogen Doping and Reduction of Graphene Oxide
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DOI：
10.1021/ja907098f
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发表时间：
2009-11-04
影响因子：
15
通讯作者：
Dai, Hongjie
中科院分区：
文献类型：
--
作者：
Li, Xiaolin;Wang, Hailiang;Dai, Hongjie
我们开发了一种简单的化学方法，通过在氨中对GO进行热退火来获得大量的N掺杂的还原氧化石墨烯（GO）片。在各种反应温度下退火的GO片的X射线光电子能谱（XPS）研究表明，N掺杂发生在低至300摄氏度的温度下，而在500摄氏度下实现类似于5%N的最高掺杂水平。N-掺杂伴随着GO的还原，其中氧水平从所制备的GO中的类似于28%下降到1100 ° C NH3反应的GO中的类似于2%。掺杂的GO的N结合构型的XPS分析在掺杂的样品中发现吡啶N，在较高温度（>= 900 ℃）下退火的GO中具有增加的季N（取代石墨烯平面中的碳原子的N）。发现GO中的氧基团负责与NH3和C-N键形成的反应。通过在H-2中热退火的具有较少氧基团的预还原GO表现出与NH3的反应性大大降低和较低的N掺杂水平。单个GO片器件的电学测量表明，在NH3中退火的GO表现出比在H-2中退火的GO更高的电导率，表明通过在NH3中退火比在H-2中退火更有效地还原GO，这与XPS数据一致。在三端器件中，N掺杂的还原GO在负栅压下具有明显的n型电子掺杂行为，具有狄拉克点（DP）。我们的方法可以导致大量的N-掺杂的，还原的GO片的合成，可用于各种实际应用。
We developed a simple chemical method to obtain bulk quantities of N-doped, reduced graphene oxide (GO) sheets through thermal annealing of GO in ammonia. X-ray photoelectron spectroscopy (XPS) study of GO sheets annealed at various reaction temperatures reveals that N-doping occurs at a temperature as low as 300 degrees C, while the highest doping level of similar to 5% N is achieved at 500 degrees C. N-doping is accompanied by the reduction of GO with decreases in oxygen levels from similar to 28% in as-made GO down to similar to 2% in 1100 degrees C NH3 reacted GO. XPS analysis of the N binding configurations of doped GO finds pyridinic N in the doped samples, with increased quaternary N (N that replaced the carbon atoms in the graphene plane) in GO annealed at higher temperatures (>= 900 degrees C). Oxygen groups in GO were found responsible for reactions with NH3 and C-N bond formation. Prereduced GO with fewer oxygen groups by thermal annealing in H-2 exhibits greatly reduced reactivity with NH3 and a lower N-doping level. Electrical measurements of individual GO sheet devices demonstrate that GO annealed in NH3 exhibits higher conductivity than those annealed in H-2, suggesting more effective reduction of GO by annealing in NH3 than in H-2, consistent with XPS data. The N-doped reduced GO shows clearly n-type electron doping behavior with the Dirac point (DP) at negative gate voltages in three terminal devices. Our method could lead to the synthesis of bulk amounts of N-doped, reduced GO sheets useful for various practical applications.