Bimetallic FeCo metal-organic-frameworks anchored multi-walled carbon nanotubes for electrochemical nitrite sensing

A heterostructured nanocomposite modified electrode was designed as a sensitive and efficient analytical tool for nitrite determination. The nanocomposite constructed from different building blocks was fabricated by ultrasonically growing bimetallic FeCo metal-organic framework (MOF) in the well-dispersed multi-walled carbon nanotubes (MWCNTs) suspensions at room temperature, where the MOF hybrid was extended to uniform thin film structure. Electrochemical experimental results demonstrate that the synergistic contributions from bimetallic active sites, MWCNTs and thin-film morphology endow modified electrode with dramatically enhanced catalytic activity metrics towards nitrite. Significantly, the co-doping of Fe-Co plays key role in improving the electronic conductivity and catalytic capacity of the MOF/MWCNTs composite. Thereinto, the FeCo-MOF/MWCNTs sensor displays excellent detection performance with a wide linear detection range (5∼5000 μM), outstanding selectivity and a detect limitation of 1.68 μM for nitrite. These superior findings provide new potentials application for the inspection of nitrite in environmental monitor.