pH-Switchable electroactive composite films of carboxylated multi-walled carbon nanotubes and Prussian blue

Abstract

Here the combination of carboxylated multi-walled carbon nanotubes (CMWCNTs) and Prussian blue (PB) for fabricating pH-responsive electroactive composite thin films is reported. The as-prepared CMWCNT@PB composite films were found to change their electrochemical behaviors in response to the solution pH, including their cyclic voltammetric and the corresponding electrochromic behaviors. The electrochromic state of PB could be switched on and off by the solution pH. Furthermore, a linear relationship was found between the peak-to-peak potential separation of the cyclic voltammogram of PB and the solution pH, indicating that the composite film modified electrode might be useful for the development of novel pH sensors. The approach for the fabrication of pH-responsive electrochemical composite films demonstrated here should be generalizable to other redox nanomaterials.