Efficient and selective sensing of nitrogen-containing gases by Si2BN 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 Si₂BN monolayer. Our rigorous simulations reveal that the representative members of nitrogen-containing gases (NCGs) such as NO, NO₂ and NH₃ binds extremely strongly on pristine Si₂BN monolayer. However, a strong dissociative adsorption in case of NO and NO₂ would poison the Si₂BN and ultimately reversibility of the monolayer would be compromised. Exploring the sensing mechanism in more realistic pre-oxidized conditions, the binding characteristics of O₂@Si₂BN changed dramatically, resulting into much lower adsorption in associative manner for all NO, NO₂ and NH₃. A visible change in work function indicates the variation in conductivity of O₂@Si₂BN upon the exposure of incident gases. Sustainable values of binding energies would also ensure a quick recovery time that makes O₂@Si₂BN an efficient nano sensor for pollutants like NCGs.