| Summary: | 碩士 === 中原大學 === 化學研究所 === 106 === By means of density functional theory (DFT) calculation, we used the carbon nanotubes with different content of doped boron as potential metal-free catalysts for the CO oxidation. In order to find the possible active sites for CO oxidation, we investigated the O2 -adsorption behavior on different position of 1 and 2 B-doped carbon nanotubes and find the most stable structures of adsorbed O2 are flat on C-B site of both nanotubes with the adsorption energies of -0.85 and -1.29 eV, respectively.
Then we investigated the catalytic reaction paths of CO oxidation, divided into two parts: (1) CO + O2* → CO2 + O*, where the activation energy required for B-doped and BB-doped catalysts are 0.34 eV and 0.42 eV, respectively; (2) O* + CO → CO2: the activation energy required for BB-doped is 0.14 eV. The reaction is through the Eley-Rideal mechanism (ER) to produce carbon dioxide. After two CO oxidation processes, the carbon nanotubes can be recovered to their original structures and recycled.
After calculation, we found that B-doped carbon nanotubes not only improved adsorption capacity of O2, but also reduced the activation energy of CO oxidation. According to our research, the higher stability of O2 , the more boron-doped content.
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