Adsorption of CO and NO molecules on SiC nanotubes and nanocages: DFT study

Silicon carbide (SiC) nanostructures have attracted extensive researches regarding their unique properties. Surface modification of the SiC nanotubes and nanocages can be useful for developing their potential applications to the gas sensors. In this paper we have studied the adsorption properties of the CO and NO molecules at different situations on a zigzag SiCNT(10,0) and armchair SiCNT(6,6) nanotubes and Si12C12 nanocage using density functional theory (DFT) calculations. The spin polarized DFT with PBE functional is employed in all calculations for the total energy calculation and optimization of the considered structures. Our results reveal that both zigzag and armchair nanotubes can adsorb CO molecule due to chemisorption and physisorption processes as its binding energy in its most stable configuration is about 0.95 and 0.89 eV, respectively. The binding energy of the NO molecule to the considered SiC nanotubes and nanocages is somewhat higher than CO binding energy in its most stable configuration. The most stable configuration for NO adsorption on SiC nanotubes is inside the nanotubes with a small different binding energy value for considered zigzag and armchair SiC nanotubes. The electronic structure of the SiC nanocage interacting with CO and NO is also discussed in this paper as our results show that the geometry structure of the nanocages is very important to the adsorption properties of the CO and NO molecules. Moreover, the present results may be useful for the design of the SiC based nanodevices for gas adsorption, storage and sensors.