Electronic modulation caused by interfacial Fe-O-Co-O-Fe bonding for boosting highly efficient non-enzymic nitrite sensing

Abstract

Rational electronic modulation of metal–organic frameworks (MOFs) derived electrocatalysts is an effective strategy for rendering them capable of enhanced sensing performance, but rather challenging. Herein, we propose a combination strategy of self-templated transformation and carbonization pyrolysis for elaborately synthesizing a MOF-derived non-planar FeCo hierarchical nest-like networks (n-FeCo-HNNs) heterojunction catalyst. Owing to the excellent electrical conductivity and active site density of n-FeCo-HNNs, such non-enzymic nitrite sensor displays a wide broad detection range, excellent sensitivity, and ultralow limit of detection. Experimental and theoretical calculations clarified the electrons are extracted and rapidly transferred to the surface-active sites through the Fe-O-Co-O-Fe bridge, and then improve the reaction kinetics and boost the sensing performance for nitrite. The synergistic effect of this chemical bond established in the heterostructure unveils a new avenue for efficient electrochemical sensing.