Carbon nanomaterials, which are represented by carbon nanotubes, nanodiamond, graphene, et al., have the broad application prospects for catalysis. These materials can be not only used as high-performance support for metal or oxide active components, but also directly used as the metal-free catalysts for oxidative dehydrogenation, selective oxidation and electric catalytic reaction, etc.

Compared with the traditional metal catalysts, carbon-based catalysts possess many excellent advantages, such as modifiable surface and structure, sufficient carbon resources, high resistance against acid and alkali corrosions. Furthermore, their acid-base properties, catalytic activity and selectivity to special product can be tuned through the chemically doping with heteroatoms of nitrogen, boron and phosphorus into the carbon nanostructure. Therefore, the research on doped carbon nanomaterials has become one of the topics in the areas of carbon and catalysis over the world.

On the basis of previous researches on metal-free catalysis, the group of Prof. Jian Zhang in the Ningbo Materials Technology and Engineering (NIMTE), the Chinese Academy of Sciences (CAS), cooperating with Prof. Dangsheng Su (the Metal Research Institute, CAS) and Prof. Feng Peng (the South China University of Science and Technology), carried out a systematic work revealing the enhanced catalytic activity of nitrogen-doped carbon nanotube (NCNT) for oxidative dehydrogenation of propane. The NCNT were prepared by chemical vapor deposition method with controllable nitrogen contents (Figure 1). In the catalytic oxidation of propane dehydrogenation, the increase in nitrogen content of NCNT increased the selectivity and yield of the target product of propylene.

Figure 1：TEM pictures of chemical element distribution Nitrogen-doped carbon nanotubes

Further researches on chemical reaction kinetics and surface analysis showed that the graphitic nitrogen can lower the reaction order of oxygen molecule and reaction activation energy, which plays the vital role in the activation of oxygen molecule and the improvement of catalytic performance (Figure 2). This finding provides a new inspiration to catalytic reaction mechanism and structure design for doped carbon nano-system.

Figure 2： Catalytic reactions performance of propane oxidative dehydrogenation on Nitrogen-doped carbon nanotubes

The work has been published on Chemical Communications (IF=6.169，DOI: 10.1039/C3CC41500G)  

Professor Jian Zhang jzhang@nimte.ac.cn

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