Borophene nanoribbons for ultrasensitive and selective detection of toxic gases: a DFT study

Borophene nanoribbons (BNRs), having semi-metallic ferromagnetism, are promising materials for gas sensing applications. This work represents interaction behavior and electronic response of BNRs toward NO 2 , SO 2 , CO 2 , H 2 S, NH 3 , H 2 , H 2 O, N 2 and O 2 gases. The interaction energies reveal that CO 2 and H 2 display very weak interactions, with energy value of just −1.8 kcal.mol − 1 and − 0.5 kcal.mol − 1 , respectively, whereas NO 2 , H 2 S, and SO 2 , show strong interactions exhibiting energies of −22.5 kcal.mol − 1 , −20.0 kcal.mol − 1 and −11.4 kcal.mol − 1 , respectively. NH 3 demonstrates moderate interaction representing energy value of −4.6 kcal.mol − 1 . Electronic structure analysis reveals that the high level of interactions of NO 2 , H 2 S, and SO 2 with BNRs originates from significant charge transfer from the gas molecules to the nanoribbons, leading to substantial redistribution in the density of states. In contrast, CO 2 and H 2 exhibit negligible electronic perturbations upon adsorption, representing weak physisorption, which favors selectivity. However, in case of NH 3 , a moderate partial charge transfer to BNRs is observed, indicating that BNRs can selectively respond to NH₃ among small gas molecules. These findings suggest that BNRs are promising for next-generation ultrasensitive and selective gas sensing, showing stronger interactions with NO 2 , SO 2 , and H 2 S than graphene, MoS 2 , and phosphorene due to electron-deficient boron and reactive edge states.