Density Functional Study on the Formation of Sulfur-doped Configuration on the Active Site of Pyrolyzed Fe/N/C Catalyst

We study the formation of sulphur-doped configuration on the graphitic active site of pyrolyzed Fe/N/C catalyst by means of density functional theory (DFT) calculations. The active site of pyrolyzed Fe/N/C catalyst is modelled by graphitic-FeN4 structure. The most stable S-doped configuration is found when an S atom is directly bonded to one of N atom of the FeN4 site. Unfortunately, our calculation results indicate that the formation of S-doped configuration on graphitic FeN4 structure is energetically unfavourable. The incorporation of S-doping in the graphitic-FeN4 system induces strong geometrical reconstructions that breaks the planarity of the original structure