氮掺杂石墨烯的生长机理及其在乙苯选择性氧化中的应用

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.

Growth mechanism of N-doped graphene materials and their catalytic behavior in the selective oxidation of ethylbenzene

N-doped graphene materials were prepared from both inorganic and organic nitrogen sources and pyrolytic graphene oxide as the carbon substrate. Transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy were used to investigate the detailed growth mechanism of the N species in these N-doped graphene materials. The different chemical nature and binding energy of the different N species resulted in their different trends with annealing temperature. These N-doped graphene are excellent catalysts in the oxidation of ethylbenzene. A high yield of acetonphenone did not depend on the total nitrogen amount but only on the type of nitrogen species. Too much defects and N-dopants were detrimental to this reaction. A proper activation of the oxidant is needed to get good catalytic activity.