In site formation and growth of Prussian blue nanoparticles anchored to multiwalled carbon nanotubes with poly(4-vinylpyridine) linker by layer-by-layer assembly

Poly(4-vinylpyridine) (P4VB) was grafted to multiwalled carbon nanotubes (MWCNTs) by an in situ polymerization. This grafted polymer plays two roles in the synthesis of Prussian Blue (PB)/MWCNT composites: (1) a stabilizer to protect PB nanoparticles from aggregation; (2) a linker to anchor these nanoparticles on the surface of MWCNTs. The size of PB nanoparticles deposited on MWCNTs can be controlled by in site layer-by-layer coordination of Fe3+ and [Fe(CN)6]4− ions in aqueous solution. The as-prepared PB/P4VP-g-MWCNT composites were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray powder diffraction, which revealed that these PB nanoparticles were uniformly distributed on the surface of MWCNTs, and grew upon layer-by-layer assembly. A potential use of PB/P4VP-g-MWCNT composites was demonstrated as an electrocatalyst used in the electrochemical detection of l-cysteine. The as-prepared electrodes modified with PB/P4VP-g-MWCNT composites showed two reversible redox waves assigned to a fast surface-controlled processes. The analytical performance for l-cysteine detection is associated with the load of PB nanoparticles onto MWCNTs. In an optimal experiment, for these as-prepared electrodes, their detection limit of l-cysteine can be measured as low as 0.01 μM with a sensitivity 778.34 nA μM−1 cm−2.

► Carbon nanotubes were grafted with poly(4-vinylpyridine).
► Prussian blue nanoparticles were deposited on carbon nanotubes by complextion.
► The size of these nanoparticles can be controlled by layer-by-layer assembly.
► The compoistes show a superior catalytic activity to the oxidation of L-cysteine.
► The efficiency is dependent on the capacity of Prussian blue nanoparticles loaded.