A Theoretical Study Of Controllable CO₂ Capture And Desorption On 2D Carbon Nitrogen Nanomaterials

The concentration of carbon dioxide(CO2)in atmosphere has been increasingly growing since the beginning of the industrial revolution because of the excessive use of fossil energy,causing globe warming and frequent happening of natural disasters.CO2 capture attracts enormous attention because it is able to effectively reduce the CO2 emissions.The efficient strategies of CO2 separation from postcombustion(predominantly CO2/N2)and precombustion(CO2/H2 and CO2/CH4)gas mixtures are of great significance for reducing the emission of greenhouse gas and gas purification.Via the density functional theory calculations,we report comprehensive investigations of CO2,N2,CH4,and H2 adsorptions on two two-dimensional carbon nitride monolayers(C2N and C3N)with/without extra charge and electric field.We find that CO2 is adsorbed weakly on neutral C2N/C3N monolayer,and the interaction between CO2 and C2N/C3N can be enhanced considerably by applying negative charge or an external electric field to C2N/C3N.Moreover,once the charge state/electric field is switched off,CO2 is released spontaneously from the C2N/C3N.However,in contrast to the adsorption of CO2,the interaction between N2/CH4/H2 and C2N/C3N is weak under all of the above conditions.In other words,our study demonstrates that the C2N and C3N monolayers can be used as excellent materials for selective and reversible CO2 capture and gas separation through switching on/off their charge state/electric field.The investigation will provide useful information to experimental researchers for searching advanced materials and strategies for reversible CO2 capture from the gas mixtures.