Direct Oxygen-Oxygen Cleavage through Optimizing Interatomic Distances in Dual Single-atom Electrocatalysts for Efficient Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) on transition single-atom catalysts (SACs) is sustainable in energy-conversion devices. However, the atomically controllable fabrication of single-atom sites and the sluggish kinetics of ORR have remained challenging. Here, we accelerate the kinetics of acid ORR through a direct O-O cleavage pathway through using a bi-functional ligand-assisted strategy to pre-control the distance of hetero-metal atoms. Concretely, the as-synthesized Fe-Zn diatomic pairs on carbon substrates exhibited an outstanding ORR performance with the ultrahigh half-wave potential of 0.86 V vs. RHE in acid electrolyte. Experimental evidence and density functional theory calculations confirmed that the Fe-Zn diatomic pairs with a specific distance range of around 3 angstrom, which is the key to their ultrahigh activity, average the interaction between hetero-diatomic active sites and oxygen molecules. This work offers new insight into atomically controllable SACs synthesis and addresses the limitations of the ORR dissociative mechanism.

Automated summary

We accelerate the kinetics of acid oxygen reduction reaction (ORR) by using a bi-functional ligand-assisted strategy to pre-control the distance of hetero-metal atoms. The synthesized Fe-Zn diatomic pairs on carbon substrates show outstanding ORR performance with an ultrahigh half-wave potential of 0.86 V vs. RHE in acid electrolyte. The specific distance range of around 3 angstrom between Fe-Zn diatomic pairs is the key to their ultrahigh activity, averaging the interaction between hetero-diatomic active sites and oxygen molecules.