In this study, the healing of N-vacancy boron carbonitride nanosheet (NV-BC 2 NNS) and nanotube (NV-BC 2 NNT) by NO molecule is studied by means of density functional theory calculations. Two di ff erent N-vacancies are considered in each of these structures in which the vacancy site is surrounded by either three B-atoms (NB) or by two B- and one C-atom (NBC). By means of the healed BC 2 NNS and BC 2 NNT as a support, the removal of two toxic gas molecules (NO and CO) are applicable. It should be noted that the obtained energy barriers of both healing and oxidizing processes are signi fi cantly lower than those of graphene, carbon nanotubes or boron nitride nanostructures. Also, at the end of the oxidation process, the pure BC 2 NNS or BC 2 NNT is obtained without any additional defects. Therefore, by using this method, we can considerably purify the defective BC 2 NNS/BC 2 NNT. Moreover, according to the thermochemistry calculations we can further con fi rm that the healing process of the NV-BC 2 NNS and NV-BC 2 NNT by NO are feasible at room temperature. So, we can claim that this study could be very helpful in both purifying the defective BC 2 NNS/BC 2 NNT while in the same e ff ort removing toxic NO and CO gases
