Amperometric hydrogen peroxide sensor based on the use of CoFe2O4 hollow nanostructures

The authors report on the preparation of a hollow-structured cobalt ferrite (CoFe 2 O 4 ) nanocomposite for use in a non-enzymatic sensor for hydrogen peroxide (H 2 O 2 ). Silica (SiO 2 ) nanoparticles were exploited as template for the deposition of Fe 3 O 4 /CoFe 2 O 4 nanosheets, which was followed by the removal of SiO 2 template under mild conditions. This leads to the formation of hollow-structured Fe 3 O 4 /CoFe 2 O 4 interconnected nanosheets with cubic spinel structure of high crystallinity. The material was placed on a glassy carbon electrode where it acts as a viable sensor for non-enzymatic determination of H 2 O 2 . Operated at a potential of −0.45 V vs. Ag/AgCl in 0.1 M NaOH solution, the modified GCE has a sensitivity of 17 nA μM −1 cm −2 , a linear response in the range of 10 to 1200 μM H 2 O 2 concentration range, and a 2.5 μM detection limit. The sensor is reproducible and stable and was applied to the analysis of spiked urine samples, where it provided excellent recoveries. Graphical abstract Schematic of a cobalt ferrite (CoFe 2 O 4 ) hollow structure for use in electrochemical determination of H 2 O 2 . The sensor shows a low detection limit, a wide linear range, and excellent selectivity for H 2 O 2 .