Novel joint catalytic properties of Fe and N co-doped graphene for CO oxidation

Abstract

Using density functional theory, we have performed detailed calculations of the joint catalytic activity of graphene co-doped with Fe and N atoms. The Fe atom can be located on single vacancy graphene and acts as the active site. Due to the strong attraction of the Fe ion, the O–O bond length of the O₂ molecule is elongated, which decreases the bonding energy between the O atoms. The energy barrier of CO oxidization is 0.84 eV. When N atoms are doped into the graphene, the interactions between the Fe ions and O₂ molecules are stronger, and the O–O bond lengths are elongated further, which makes the desorption of the quasi-CO₂ molecule easier. The energy barriers are reduced to 0.62 eV, 0.49 eV, and 0.33 eV for graphene doped with one, two and three N atoms, respectively. The O atom remaining on the Fe ion can form a CO₂ molecule with an additional CO molecule. The produced CO₂ molecule can be released with a small or even zero energy barrier by adsorbing an O₂ molecule. The adsorbed O₂ molecule is then involved in the next reaction process, and the material can be used as a recycled catalyst.