Innovative self-assembled silver nanoparticles on reduced graphene oxide hydrogel nanocomposite for improved electrochemical hydrogen generation and sensing
Edwin Makhado, Wilson M. Seleka
Abstract
Conductive hydrogels (CHs) are widely studied for flexible sensors in hydrogen energy applications due to their excellent conductivity, flexibility, and detection capabilities. However, most CH-based sensors suffer from low sensitivity, poor stability, and weak tensile strength. Furthermore, they often rely on non-biodegradable synthetic polymers, limiting their practical applications. This study utilizes Ag@rGO hydrogel nanocomposite blended with cellulose as an electrochemical sensor for hydrogen gas detection at ambient temperature, considering its higher catalytic activity, favorable surface area, and conductivity to overcome existing limitations. Nonetheless, given that cellulose serves as a binding agent in the formation of hydrogel, its characteristics like biodegradability, compatibility, and the ability to react to various chemical systems are transferred to the surface of the Ag@rGO hydrogel-based sensor. The measured sensitivity for hydrogen detection of the Ag@rGO nanocomposite and Ag@rGO hydrogel nanocomposite was found to be 188.38 and 329.85 µA.M, respectively. The limits of detection were recorded at 0.92 and 0.63 µM, with response/recovery times of 0.6/0.9 s and 0.3/0.6 s. The proposed electrochemical sensor offers an exciting approach for the detection of hydrogen gas. The sensor was fabricated and its microstructure characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Its electrochemical performance, sensing efficiency, interference resistance, and stability were assessed using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). This study explores the use of biopolymer-blended conductive hydrogels as innovative channel materials for developing gas sensors that are both highly flexible and sensitive.