title: Nitrogen-doped carbon nanotube as a potential metal-free catalyst for CO oxidation.
abstract: We elucidate the possibility of nitrogen-doped carbon nanotube as a robust catalyst for CO oxidation. We have performed first-principles calculations considering the spin-polarization effect to demonstrate the reaction of CO oxidation catalyzed by the nitrogen-doped carbon nanotube. The calculations show that O2 species can be partially reduced with charge transfer from the nitrogen-doped carbon nanotube and directly chemisorbed on the C-N sites of the nitrogen-doped carbon nanotube. The partially reduced O2 species at the C-N sites can further directly react with a CO molecule via the Eley-Rideal mechanism with the barriers of 0.45-0.58 eV for the different diameter of nanotube. Ab initio molecular dynamics (AIMD) simulations were performed and showed that the oxidation of CO occurs by the Eley-Rideal mechanism. The relationship between the curvature and reactivity of the nitrogen doped carbon nanotube was also unraveled. It appears that the barrier height of the rate-limiting step depends on the curvature of the nitrogen-doped carbon nanotube in the trend of (3,3)-NCNT < (4,4)-NCNT < (5,5)-NCNT (decreases with increased curvature). Using this relationship, we can predict the barriers for other N-doped carbon nanotubes with different tube diameters. Our results reveal that the nitrogen doped carbon nanomaterials can be a good, low-cost, and metal-free catalyst for CO oxidation.
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, Chungli District, Taoyuan City, 32023, Taiwan. htchen@cycu.edu.tw.
authors.forename: I-Hsiang
authors.initials: IH
authors.lastname: Lin
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, Chungli District, Taoyuan City, 32023, Taiwan. htchen@cycu.edu.tw.
authors.forename: Yu-Huan
authors.initials: YH
authors.lastname: Lu
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, Chungli District, Taoyuan City, 32023, Taiwan. htchen@cycu.edu.tw.
authors.forename: Hsin-Tsung
authors.initials: HT
authors.lastname: Chen