Intersite metal-metal interactions in CuFe diatomic single-atom pairs coordinated with S and N-ligands for efficient oxygen reduction reaction and rechargeable zinc-air batteries

Single-atom catalysts (SACs) are about to undergo the next paradigm shift, thanks to diatomic single atoms (DSACs), which provide excellent performance due to the synergistic effect of nearby bimetallic pairs. However, the synthesis of DSACs with precise bimetallic structures is currently limited, and it continues to be difficult to rationally design such catalysts and comprehend their structure-activity relationships. Herein, a facile practical pre-coordination approach followed by a carbonization process was used to rationally design DSACs of copper (Cu) and iron (Fe) coordinated with sulfur (S) and nitrogen (N) atoms in a rhombic dodecahedral carbon matrix (S CuFe−N C). Experimental and theoretical findings signify that the synergistic effect of Cu Fe DSACs may induce the electronic charge redistributions and thereby enhances the ability of oxygen intermediates adsorption/desorption kinetics of S CuFe−N C. In addition, the coordinated S and N-ligands may preserve the structural stability of S CuFe−N C. This can result in regulated electronic configurations, and it is especially beneficial for the enhancement of ORR because of the rapid release of electrons. Consequently, the S CuFe−N C exhibited an enhanced ORR performance than all other samples including Pt/C. Besides, the rechargeable ZAB based on the S CuFe−N C catalyst delivered a higher power density (∼162.01 mW cm −2 ) than the Pt/C-based ZAB (∼136.81 mW cm −2 ). Also, the S CuFe−N C-based ZAB possesses a higher specific capacity (∼809.43 mAh g −1 ) than that of Pt/C (∼787.33 mAh g −1 ). Our findings provide a new avenue for rationally designing and precisely tuning the atomically dispersed low-cost non-precious heteronuclear DSACs for electrocatalysis and beyond.