| Abstract: | Exploration of new property/function of nanomaterials is always a strong impetus in the nanoscience field. Here, a new method of electrochemical conversion (ECC) of magnetic nanoparticles (MNPs) is proposed to endow MNPs with signal generation ability for sensing. Briefly, high potential was applied to split H2O to generate acid, while Fe3O4 MNPs reacted with H+ and produce ferric/ferrous ions, which further reacted with K4Fe(CN)6 to yield Prussian blue (PB) through potential cycling. The ECC method worked well on both home‐made and commercial MNPs with different sizes. The generated PB possessed strong electrochemical activity for further applications. Interestingly, an uneven deposition of PB on working electrode and undesired contamination of the reference and counter electrodes were found when using commercial integrated three‐electrode chip. A 3D‐printed electrochemical cell was designed to facilitate the ECC and avoid drawbacks of commercial integrated electrode. The 3D‐printed electrochemical cell was proven to solve the problem above through spatial separation of electrodes and thus facilitated the ECC process. An electrochemical sensor for H2O2 detection based on the catalysis ability of ECC‐based PB exhibited a linear response from 5 μM to 1 mM, a high sensitivity of 269 μA mM?1 cm?2 and a low detection limit of 0.16 μM (S/N=3), which suggests its promising application prospect in electrochemistry‐related analysis. |
