Adsorption and Activation of O2 on Nitrogen-Doped Carbon Nanotubes

The adsorption and activation of triplet O-2 on the surface of nitrogen-doped carbon nanotube (NCNT) with different diameter and length were investigated. It was found that, rather than the unfavorable adsorption on normal carbon nanotube (CNT), the adsorption of O-2 on NCNT was obviously exothermic and the electron transition of O-2 happened in the adsorption process. The oxygen adsorbed on NCNT showed an interesting electron configuration which was similar to the active oxygen anion. The spin density, charge, and bond length of O-2 changed with the size of NCNT. In combination with the recent results reported by Dai et al. (Science, 2009, 323, 760), it is reasonable to believe that these NCNTs should be a potential metal-free catalyst. The results presented here should be useful for designing and developing effective catalyst based on NCNT.