Efficient and selective sensing of nitrogen-containing gases by Si ₂ BN nanosheets under pristine and pre-oxidized conditions

Motivated by the promise of two-dimensional nanostructures in the field of gas sensing, we have employed van der Waals corrected density functional theory calculations to study the structural, electronic and gas sensing propensities of the recently designed Si ₂ BN monolayer. Our rigorous simulations reveal that the representative members of nitrogen-containing gases (NCGs) such as NO, NO ₂ and NH ₃ binds extremely strongly on pristine Si ₂ BN monolayer. However, a strong dissociative adsorption in case of NO and NO ₂ would poison the Si ₂ BN and ultimately reversibility of the monolayer would be compromised. Exploring the sensing mechanism in more realistic pre-oxidized conditions, the binding characteristics of O ₂ @Si ₂ BN changed dramatically, resulting into much lower adsorption in associative manner for all NO, NO ₂ and NH ₃ . A visible change in work function indicates the variation in conductivity of O ₂ @Si ₂ BN upon the exposure of incident gases. Sustainable values of binding energies would also ensure a quick recovery time that makes O ₂ @Si ₂ BN an efficient nano sensor for pollutants like NCGs.