Adsorption of CO2 on graphene surface modified with defects

Abstract

Graphene doped with nitrogen acts as a metal-free electrode, it has three times more catalytic activity than graphene and achieves the catalytic activity of the Pt. It has been proposed as an alternative to Pt since it would be cheaper and easier to produce. We report a computational analysis using dispersed corrected DFT calculations and molecular dynamics (MD). Adsorption properties, electronic properties, and stabilities in time of the adsorption of CO2 molecule on defected graphene were studied. The MD was carried out at room temperature and in time of 0.8 ps. The defective graphene chosen has the following defects: Graphitic-N type defect, Pyridinic-N type defect, and a vacancy in graphene layer. The adsorption analysis gives the interaction type existing between the CO2 molecule and the defected graphene, which is in the physisorption range. Also, it is proven here that the type of defect defines the interaction. Graphene with a vacancy and Pyridinic-N systems are p-type doping, indicating that electrons on the surfaces are pulled out and directed to the CO2 molecule. The most stable system at room temperature is the graphitic-N, which present n-type doping, pulling electrons from the CO2 molecule and stimulating the electrocatalytic activity for CO2 conversion.