A novel electroactive biopolymer-graphene oxide nanocomposite membrane for high-performance electrochemical sensing of ethylene

Abstract

This study focuses on formulating an electroactive composite membrane using polyvinyl alcohol (PVA), chitosan (CHT), and graphene oxide (GO), specifically emphasizing its application in electrochemical ethylene detection. Through the surface functionalization of the PVA-CHT-GO membrane via GO activation, the nanocrystallite GO-based composite, when incorporated into a microelectrode chip, exhibited a transformative enhancement in electrochemical ethylene sensing. Comprehensive characterizations of both the synthesized GO and the PVA-CHT-GO composite membranes were conducted by employing X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Raman spectroscopy, Energy Dispersive X-ray spectroscopy (EDS), Field emission scanning electron microscopy (FE-SEM), and Thermal gravimetric analysis (TGA). The XRD pattern provides insights into the stacking height, interplanar spacing, and the number of layers along the (002) direction. The synthesized GO's average nano-crystallite size was determined to be 10.38 nm. The Raman spectrum revealed prominent D and G bands at 1353 and 1591 cm-1, respectively. FE-SEM images depicted the overlapping of GO nanolayers, each layer having a thickness in the range of 20–30 nm. Following surface activation, thin layers developed on the membrane surface, with numerous folds accumulating, exhibiting thickness in the range of 20–50 nm. The intricate characterization underscored the structural and morphological features of the membrane, enhancing our understanding of its surface properties. The effectiveness of ethylene detection using the GO-activated PVA-CHT-GO membrane was evaluated via cyclic voltammetry (CV) measurements. These measurements confirmed the membrane's efficiency, demonstrating ultra-sensitive ethylene detection, even upon initial exposure to ethylene.