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

Highlights: • BC₃-based sensor has a low and moderate sensitivity to CO and NH₃, respectively. • BC₃-based sensor has high potential for NO and NO₂ detection. • NO₂ could be dissociated into NO and O species through the adsorption on the BC₃. • BC₃ is a promising catalyst for dissociation of NO₂ gas molecule. - Abstract: The adsorption behaviors of toxic gas molecules (NO, CO, NO₂, and NH₃) on the graphene-like boron carbide (BC₃) are investigated using first-principle density functional theory. The graphene-like BC₃ monolayer is a semiconductor with a band gap of 0.733 eV. It is discovered that all the above gas molecules are chemisorbed on the BC₃ sheet while they retain their molecular forms. It is also revealed that the NO₂ gas molecule could be dissociated into NO and O species through the adsorption process. The amounts of charge transfer upon adsorption of CO and NH₃ gas molecules on the BC₃ are found to be small. 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 the BC₃, significant charges are transferred from the molecules to the BC₃ sheet, causing a semiconductor-metal and semiconductor-p type semiconductor transition. Our study suggests that the BC₃-based sensor has a high potential for NO and NO₂ 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.