Carbon nanotube/reduced graphene oxide nanocomposite formed at interfacial method: Properties and potential electroanalytical applications

This work presents a new route to produce carbon nanotube/reduced graphene oxide (CNT/rGO) nanocomposites using the interfacial method to produce high-performance electroanalytical sensing. The nanocomposite thin-film is formed at the cyclohexane/water immiscible interface after stirring of a mixture of CNT and rGO in the biphasic solution and can be transferred to any planar substrate. As a proof-of-concept, the nanocomposite film was transferred to a boron-doped diamond electrode. Improved electrochemical sensing of molecules of pharmaceutical (phenolic compounds (dopamine and catechol)) and forensic interest (trinitrotoluene (TNT)) under stationary (cyclic voltammetry) and hydrodynamic (amperometry) conditions was verified in comparison with unmodified and modified surfaces with rGO and CNT using the same method. Electrochemical impedance spectroscopy also evidenced the faster electron transfer for a redox probe on the nanocomposite surface. Scanning electron microscopic images show the interaction of rGO with CNT and Raman spectra revealed the defect density. Amperometric and voltammetric detection of phenolic compounds and TNT, respectively, showed synergistic properties of CNT and rGO on the response of nanocomposite, which resulted in highly sensitive sensors with superior performance in comparison with electrochemical sensors based on CNT or rGO already reported (nanomolar detection limits for dopamine, catechol, and trinitrotoluene). Hence, this new protocol offers great promises to develop improved electrochemical sensors for a wide range of analytes, including pharmaceutical and forensic applications.