Strongly coupled iron selenides-nitrogen-bond as an electronic transport bridge for enhanced synergistic oxygen electrocatalysis in rechargeable zinc-O2 batteries

Abstract

Hybrid of transition-nitrogen-doped carbon (M-NC) and transition metal nanomaterials into one single catalyst has been considered as the most promising strategy for constructing bifunctional oxygen reduction and evolution reaction (ORR/OER) catalysts. However, the direct evidence of bridged-bond between ORR and OER catalyst which is crucial for enhancing the electrocatalytic performance, has never been confirmed in the literature. In this manuscript, we exploited a new class of strongly coupled Fe2NiSe4@Fe-NC hybrid material, in which the Fe2NiSe4 nanocubes strongly coupled to the Fe-NC through the selenium-graphitic-nitrogen bond (Se-GNG). Additional characterizations and DFT calculations have confirmed that the Se-GNG bond can act as a bridge to deliver the electrons from Fe and Ni to the graphitic-N (Quaternary-N), which is beneficial to enhance both the ORR/OER activity and durability. Due to this strong electronic interaction, this novel hybrid Fe2NiSe4@Fe-NC electrocatalyst reveals superior performance and durable operation without chemical instability towards both ORR/OER.