A comparative theoretical study of CO2 sensing using inorganic AlN, BN and SiC single walled nanotubes

The adsorption of CO2 gas molecule on the armchair (4,4) aluminum nitride (AlN), boron nitride (BN) and silicon carbide (SiC) nanotubes are investigated using DFT calculations. The combining processes of gas adsorption on all different sites of AllNT, BNNT and SiCNT are exothermic and the relaxed geometries are stable. Our results reveal that the interaction between CO2 molecule and BNNT and SiCNT are weak, so that the adsorption of CO2 onto the BNNT and SiCNT is physisorption process. However, the AlNNT exhibits strong affinity toward the CO2 gas molecule. Compared with the weak adsorption on BN and SiC nanotubes, CO2 molecule tends to be strongly chemisorbed to the AlNNT with appreciable adsorption energy (about - 117 kJ/mol). The adsorption of CO2 molecule onto the AlNNT would affect the electronic conductance and mechanical properties, which could serve as a signal of gas sensor. It seems that the considerable charge transfer from AlNNT to CO2 molecule is occurred due to the reduction of the HOMO-LUMO energy gap. Based on the obtained results, it is expected that AlNNT could be a promising candidate in gas sensor devices for detecting the CO2 molecule. (C) 2013 Elsevier B.V. All rights reserved.