Antifouling double layers of functionalized-multi-walled carbon nanotubes coated ZnO for sensitive and selective electrochemical detection of catechol

Abstract

Herein, a novel catechol sensor made of double-layers of functionalized multi-walled carbon nanotubes coated zinc oxide on a glassy carbon electrode (fMWCNTs/ZnO@fMWCNTs/GCE) is synthesized. The FTIR spectrum reveals that the ZnO NPs are successfully functionalized on the fMWCNT while SEM analysis shows granular colloids on the surface of ZnO@fMWCNTs nanocomposites. The XRD study confirms the crystalline nature of the ZnO peaks and the ZnO interaction with fMWCNTs structure. The fabricated sensor responds to a wide linear range of CC concentrations from 10 µM to 200 µM and sensitivity of 0.0022 µA/µM.cm² with a detection and quantification limit of 0.027 µM and 0.092 µM, respectively. Both of the limits are better than previously reported ZnO and fMWCNTs sensors. In addition, the developed fMWCNTs/ZnO@fMWCNTs/GCE demonstrates that the electron transfer is regulated by the adsorption-controlled process and can successfully detect catechol in real water samples with an excellent selectivity against hydroquinone (HQ), phenol (ph), and penta-chlorophenol (p-chph). The developed sensor exhibits satisfactory analytical performance including operational stability of 94.5%, good repeatability with a relative standard deviation (RSD) of 2.15%, and reliable reproducibility of 8 electrodes with an RSD of 3.93%.

Research Highlights

• An antifouling double-layered functionalized multi-walled carbon nanotubes (fMWCNTs) coated zinc oxide nanoparticles (ZnO NPs) is synthesized.

• The nanocomposite (fMWCNTs/ZnO@fMWCNTs) was fabricated using a one-step in-situ adsorption method.

• In the new design of the fabricated nanocomposite, the diffusion of electrons is improved by the adsorption control mechanism.

• The developed sensor is highly sensitive and selective for sensing catechol.

• It exhibits stable and reproducible responses for practical and real analysis of catechol.

Graphical Abstract

Keywords:

• Antifouling techniques
• catechol
• colloids
• MWCNTs
• electrochemical detection
• sensing interfaces
• ZnO NPs

Acknowledgments

We acknowledge the Algerian ministry of higher education and scientific research and also the general agency of scientific research and technological development (DGRSDT) for their support.