Adsorption of toxic gases on borophene: surface deformation links to chemisorptions

Abstract

β₁₂ borophene has received great attention because of its intriguing mechanical and electronic properties. One of the possible applications of borophene is gas sensing. However, the interaction between common gases and β₁₂ borophene remains to be clarified. In this work, we study the interactions of β₁₂ borophene towards five hazardous gases, namely, CO, NO, NH₃, NO₂, and CO₂ using various non-empirical van der Waals density functionals and provide an insight into the adsorption behavior of borophene. The adsorption mechanism and molecular vibrations are discussed in great detail. Among the gases considered, CO₂ is physisorbed while other gases are chemically bonded to β₁₂ borophene. We also demonstrate that the deformation at the ridge of borophene enables its active p_z orbital to strongly hybridize with frontier orbitals of the studied polar gases. Consequently, borophene is predicted to interact strongly with CO, NO, NH₃, and especially NO₂, making it a sensitive sensing material for toxic gases.