Activity of N-coordinated multi-metal-atom active site structures for Pt-free oxygen reduction reaction catalysis: Role of ∗OH ligands

Abstract

We report calculated oxygen reduction reaction energy pathways on multi-metal-atom structures that have previously been shown to be thermodynamically favorable. We predict that such sites have the ability to spontaneously cleave the O2 bond and then will proceed to over-bind reaction intermediates. In particular, the ∗OH bound state has lower energy than the final 2 H2O state at positive potentials. Contrary to traditional surface catalysts, this ∗OH binding does not poison the multi-metal-atom site but acts as a modifying ligand that will spontaneously form in aqueous environments leading to new active sites that have higher catalytic activities. These ∗OH bound structures have the highest calculated activity to date.