Structural and electronic properties of the adsorption molecules on Co and Fe/N-doped graphene towards the application in direct liquid fuel cell

Abstract

Co and Fe-nitrogen-doped graphene model (MN4) with an N/C ratio of 0.043 is tested for oxygen reduction reaction. The models and calculations were done using density functional theory (DFT). Four molecules, namely O2, OOH, OH, and H2O2, are adsorbed on the Co and Fe atom of MN4, and the changes in the adsorption energy are compared with the graphene model with MN4 model with the N/C ratio of 0.051. With the exception of the FeN4-OO complex, the adsorption energy for molecules in MN4 increases when the ratio is changed. Other molecules such as methanol, carbon monoxide, ethanol, formic acid, and glycerol also have been tested for adsorption on the Co and Fe atom to study its potential for the reaction using these catalyst models. The results show that these models display little positive activities for the oxidation reaction at anode direct liquid fuel cell (DLFC) as alternative energy. The competitive reaction may occur in DLFC if these catalysts are used as cathode catalyst in DLFC. Both models have a high potential to proceed with H2O production in the oxygen reduction reaction. Furthermore, these model catalysts may also suitable for polymer electrolyte membrane fuel cell (PEMFC) if pure hydrogen is used as fuel.