Multifunctional carbon nanotubes/ruthenium purple thin films: preparation, characterization and study of application as sensors and electrochromic materials

Abstract

This work reports the preparation, characterization and application as both electrochromic materials and electrochemical sensors of novel materials: carbon nanotubes/ruthenium purple nanocomposites. Using an innovative route based on a heterogeneous electrochemical reaction involving iron oxide species encapsulated within the cavities of the carbon nanotubes, the nanocomposite materials were obtained as transparent thin films deposited over transparent electrodes. Several experimental parameters related to the nanocomposite synthesis were evaluated and related to the characteristics of the obtained materials, such as morphology and stability. The films were characterized by UV-Vis and Raman spectroscopy, scanning electron microscopy, X-ray diffraction, cyclic voltammetry and UV-Vis and Raman spectroelectrochemistry. Four different materials were applied as H₂O₂ sensors and exhibited impressive analytical parameters, including a limit of detection of 1.27 nmol L⁻¹ and a sensitivity of 39.6 A M⁻¹ cm⁻². These nanocomposites also showed great electrochromic properties, with high stability and coloration efficiency over 95% maintained during stability cycles.