Co-Zn single atoms anchored carbon nanotubes derived from anti-perovskite carbides for boosted hydrogen evolution and oxygen reduction reactions

Atomically dispersed Co-Zn single-atoms anchored on carbon nanotubes were synthesized through a self-decomposition approach, exhibiting the remarkable difunctional properties for hydrogen evolution and oxygen reduction reactions. [Display omitted] •Co-Zn single-atom anchored on carbon nanotubes is synthesized by a novel self-decomposition strategy.•Co-Zn single-atoms are identified to be the Co-Zn-N6 configuration in the carbon matrix.•The Co active sites are optimized by the strong electronic coupling effect between Co and Zn dual atoms.•Co,Zn SAs@Co-CNTs can employ as an efficient difunctional electrocatalyst for HER and ORR. The optimization of the single-atom catalysts (SACs) performance has emerged as a rising star in recent years, however, the synergistic effect for the diatomic sites (DASs) electrocatalysts remains a grand challenge. Herein, we propose a self-decomposition approach for the synthesis of atomically dispersed Co-Zn single atoms anchored on Co-embedded carbon nanotubes (Co,Zn SAs@Co-CNTs) derived from anti-perovskite carbides. Experimental results and theoretical calculations demonstrate that the synergy effect between Co and Zn DASs accelerates the formation of OOH* and the dissociation of OH* in the oxygen reduction reaction (ORR), and reduces the adsorption–desorption energy barrier of H* in the hydrogen evolution reaction (HER). As expected, the Co,Zn SAs@Co-CNTs exhibits superior HER (acid: ɳ10 = 142 mV; alkaline: ɳ10 = 89 mV) and ORR (E1/2 = 0.92 V) activities with excellent operational stability, outperforming the 20 wt% Pt/C benchmark. This study highlights a new insight for modulating the electronic structure of active centers for electrocatalysts by dual-atom site.