Understanding of oxygen reduction reactivity improvement of FeNC catalysts by introducing sulfonyl groups

Abstract

Non-precious metal catalysts such as FeNC have received a lot of attention to replace platinum for oxygen reduction reaction(ORR) in low temperature proton exchange membrane fuel cells(PEMFCs). Despite these concerns, enough fundamental study has not been done yet. In a few fundamental studies, previously reported, a new design was introduced to enhance the ORR kinetic activity of FeNC. It is a theoretical strategy to change the d-orbital electron density of single atom iron sites by doping sulfur functionalities; electron withdrawing / donating groups, and to modify intermediate binding energy and kinetic activity of ORR. This work confirms whether the increase in kinetic activity due to the introduction of sulfur functionalities increase in intrinsic activity or an increase in active site density, and proves the validity of previous studies.