DFT study of adsorption behavior of NO, CO, NO2, and NH3 molecules on graphene-like BC3: A search for highly sensitive molecular sensor

The adsorption behavior of toxic gas molecules (NO, CO, NO2, and NH3) on graphene-like BC3 are investigated using first-principle density functional theory (DFT). The most stable adsorption configurations, adsorption energies,binding distances,charge transfers,electronic band structures,and the conductance modulations are calculated to deeply understand the impacts of the molecules above on the electronic and transport properties of the BC3 monolayer. The graphene-like BC3 monolayer is a semiconductor with a band gap of 0.733 eV. The semi-metal graphene has a low sensitivity to the abovementioned molecules. However, it is discovered that all the above gas molecules are chemically adsorbed on the BC3 sheet with the adsorption energies less than -1 eV. The NO2 gas molecule is totally dissociated into NO and O species through the adsorption process, while the other gas molecules retain their molecular forms. The amounts of charge transfer upon adsorption of CO and NH3 gas molecules on BC3 are found to be small. Hence, the band gap changes in BC3 as a result of interactions with CO and NH3 are only 4.63% and 16.7%, indicating that the BC3-based sensor has a low and moderate sensitivity to CO and NH3, respectively. Contrariwise, upon adsorption of NO or NO2 on BC3, a significant charge is transferred from the molecules to the BC3 sheet, causing a semiconductor-metal transition. It is found that the BC3-based sensor has high potential for NO detection due to the significant conductance changes, moderate adsorption energy, and short recovery time. More excitingly, the BC3 is a likely catalyst for dissociation of the NO2 gas molecule. Our findings divulge promising potential of the graphene-like BC3 as a highly sensitive molecular sensor for NO and NH3 detection and a catalyst for NO2 dissociation