A DFT study on the N2O reduction by CO molecule over silicon carbide nanotubes and nanosheets

摘要

In this work, we study the nitrous oxide (N2O) reduction by CO over zigzag (6,0) silicon carbide nanotubes (SiCNT) and nanosheets (SiCNS) by means of density functional theory calculations. Different N2O and CO adsorption configurations are examined over these surfaces. The results indicate that the adsorption of N2O via a [3 + 2]-cycloaddition is the most favorable structure over the SiCNT and SiCNS. For both surfaces, the N2O reduction proceeds via two different steps: (1) N2O -> N-2 + O*, and (2) O* + CO -> CO2. In addition, the length and curvature effects of the SiCNT on the adsorption of gas molecules are studied in detail. The activation energy (E-act) of the N2O -> N-2 + O* step over (6,0) SiCNT (0.71 eV) is considerably smaller than that of SiCNS (1.12 eV). Also, with the reduction of the tube diameter, the N2O decomposition reaction proceeds with a smaller E-act.