A highly sensitive sensor for the detection of nitrite based on a nanoporous Fe2O3–CoO composite

Abstract

A nanoporous (NP) Fe₂O₃–CoO nanoparticle composite was easily fabricated by mild dealloying of the ternary alloy Fe₅Co₅Al₉₀ in NaOH solution. Electrochemical characterization shows that the NP-Fe₂O₃–CoO composite has a high electrochemical sensing activity towards nitrite, with a fast response less than 3 s, a wide linear range of 0.2–16.2 mM, and a low detection limit of 0.1 μM. In particular, long-term sensing tests demonstrated that the NP-Fe₂O₃–CoO composite has remarkable sensing durability with almost no activity loss for nitrite detection after 4000 s. The proposed sensor based on the NP-Fe₂O₃–CoO composite is effective for the determination of nitrite in sausage samples, thus having great potential for electrochemical nitrite sensing.