Prussian blue modified carbon black nanoparticles enabling record sensitivity of hydrogen peroxide electrochemical sensors.

We report on the deposition of Prussian blue nanoparticles onto the carbon black supports in course of reduction of FeCl3/K3Fe(CN)6 equimolar mixture by hydrogen peroxide. This one-pot synthesis eliminates the use of volatile organic solvents as well as additional synthetic or mixing steps. With an increase of carbon black loading, the hydrodynamic size of the resulting nanocomposites displays the well-defined maximum and reaches the plateau at 115 ± 10 nm. Modified electrodes were fabricated by simple drop-casting of the nanoparticle suspensions onto the surface of screen-printed carbon structures. The highest electroactivity of Prussian blue was achieved at a carbon-to-iron molar ratio of 35. The corresponding hydrogen peroxide sensors exhibit ultra-high sensitivity (1.5 ± 0.1 A·M-1·cm-2), approximately 1.5-2 fold higher than sensors based on solely adsorbed Prussian blue nanoparticles or the same mixed with carbon black after synthesis. The low-cost and easily prepared carbon black/Prussian blue nanoparticles are promising for application in various fields of electroanalysis.