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以热解氧化石墨烯材料为碳基底,分别使用有机氮源和无机氮源对其进行氮掺杂处理, 制备了一系列氮掺杂石墨烯材料.采用透射电子显微镜、扫描电子显微镜、拉曼光谱和X射线光电子能谱等表征方法考察了氮掺杂石墨烯的生长机理. 结果表明, 随着制备过程中退火温度的改变, 氮掺杂石墨烯中不同氮物种的含量有显著差别.这种差异是由不同氮物种化学环境的差异所导致的.所制备的含氮石墨烯材料对乙苯选择性氧化制苯乙酮反应均表现出优良的催化活性.其中,石墨氮的含量对于提高苯乙酮收率起到至关重要的作用.此外,通过氧化剂控制活化的方法可以消除过多的结构缺陷和过量氮掺杂对催化反应的不利影响, 有效提升氮掺杂石墨烯的催化活性.
A series of nitrogen-doped graphene materials were prepared by pyrogenic graphene oxide (EGG) as carbon substrate and nitrogen-doped with organic and inorganic nitrogen sources, respectively.Transmission electron microscopy, scanning electron microscopy, Spectroscopy and X-ray photoelectron spectroscopy were used to characterize the growth mechanism of nitrogen-doped graphene.The results showed that the content of different nitrogen species in nitrogen-doped graphene was significantly different with the change of annealing temperature in the preparation process. The difference of species is caused by the difference of the chemical environment of different nitrogen species. The prepared nitrogen-containing graphene material shows good catalytic activity for the selective oxidation of ethylbenzene to acetophenone. Among them, the content of graphite nitrogen is increased The yield of acetophenone plays a crucial role.In addition, the activation by oxidant can eliminate the excessive structural defects and the adverse effect of excessive nitrogen doping on the catalytic reaction, and effectively enhance the catalytic activity of nitrogen-doped graphene .