Achieving Tunable Adsorption Selectivity and Sensitivity of Boridenes for Gas Detection with Surface O-termination Engineering

Abstract

This study utilizes density functional theory (DFT) to explore the potential of use Boridenes as gas-sensing materials for common organic and inorganic gases, including C2H2, C2H4, C2H6, C4F7N, CH2O, CH4, CO, CO2, H2, H2O, N2, NO, NO2, O2, SF6 and SO2. The adsorption atomic configurations and adsorption energies are calculated for all gas species in Mo4/3B2-Mo4/3B2O2 series, elucidating the change of adsorption mechanism from chemisorption for the bare Mo4/3B2 monolayer to the physisorption in the case of Mo4/3B2O2 monolayer, and also manifesting the significance of O-terminations on the adsorption properties of Boridenes for the considered gas species. In addition, the gas-sensing parameters including recovery time, sensitivity and selectivity are evaluated for Mo4/3B2 and Mo4/3B2Ox monolayers to demonstrate the tunable sensing performance of Boridenes for target gas species by tailoring the surface functional groups. The results reveal that the bare Mo4/3B2 show the promising reusability and selectivity for detecting insulating gases (SF6 and C4F7N) and their dissociated products (SO2 and CO). While the presence of O-terminations greatly improves the recovery time (10-8 s), sensitivity (100.0%) and selectivity (exclusive NO adsorption) of sensing NO pollutants in the air for Mo4/3B2O2 monolayer. Overall, this work is expected to benefit the research and development of gas-sensing materials based on Boridenes for various application scenarios in the future experimental study.