In order to reduce the greenhouse effect caused by the rapid increase of CO2 concentration in the atmosphere,it is necessary to develop more efficient,controllable,and highly sensitive adsorbing materials.In this study,the adsorption behavior of CO2 on BC3 nanosheets under an external electric field was explored based on density functional theory (DFr).It was found that CO2 experienced a transition from physisorption to chemisorption in the electric field range of 0.0060-0.0065 a.u..In addition,the adsorption/desorption of CO2 is reversible and can be precisely controlled by switching on/off at the electric field of 0.0065 a.u..The selective adsorption of CO2/H2/CH4 by BC3 can also be used to realize gas separation and purification under different electric fields.This study highlighted the potential application of BC3 nanosheets as a high-performance,controllable material for CO2 capture,regeneration,and separation in an electric field.