Density Functional Theory Study of the Oxygen Reduction Reaction in a Graphene Surface Modified with S or N

Due to the high cost and scarcity of platinum resources, the design and synthesis of new materials for reducing or replacing platinum materials used in the cathode side of low temperature fuel cells has become imperative. In the last decades, novel materials to reduce or replace Pt or Pt alloys have been used as candidates in fuel cells electrodes. Carbon nanomaterials show good performance when used as supports of the active phase. On the other hand, carbon nanomaterials modified with heteroatoms such as sulfur or nitrogen has been also evaluated for the oxygen reduction reaction (ORR) in alkaline media as a promising alternative. To characterize this alternative, first-principles computational methods are useful tools to explain the influence of heteroatom doped-carbon materials on the adsorption/reaction phenomena associated with the ORR. In this context, we present the electrochemical behavior of the surface reactions on graphene doped with S or N, by computational modeling using density functional theory (DFT). We discuss the adsorption/reaction phenomena occurring during catalysis processes on graphene structures modified with dopant S or N atoms. The analysis is related to the electrochemical performance of these materials under adsorption of different functional groups that can describe the behavior of ORR in alkaline media.