As is well-known, searching for an efficient catalyst that can oxidize CO molecules is of great importance
in the removal of this poisonous gas. Using density functional theory calculations, we report the oxidation
of CO by molecular O 2 on a finite-sized silicon carbide nanotube (SiCNT) and nanosheet (SiCNS). Both
Eley–Rideal (ER) and Langmuir–Hinshelwood (LH) oxidation mechanisms are considered. The CO oxida-
tion by O 2 on SiCNT and SiCNS surfaces occurs via a two-step mechanism: (1) O 2 + CO - OOCO -
O ads + CO 2 and (2) O ads + CO - OCO - CO 2 , proceeding via LH and ER mechanisms, respectively. The
activation energies of these two steps over the SiCNT (SiCNS) are 0.86 (0.27) and 0.97 (0.12) eV, respec-
tively. Results indicate that the CO oxidation over the SiCNS is more favorable than that over the SiCNT,
due to its lower energy barriers. In addition, the increasing of the tube length and curvature effects on the
adsorption of an O 2 /CO molecule is also studied. This study has useful guidance for fabricating SiCNTs
and SiCNSs for CO oxidation with high activity properties.