Study of the structure and electrical properties of graphene oxide (GO) and graphene oxide+nanocellulose (GO+NC)

Abstract

Proton exchange membranes (PEMs) that function at elevated temperatures surpassing 100°C and exhibit exceptional mechanical, chemical, and thermochemical stability have garnered significant interest. This is primarily due to their practical utility in proton exchange membrane fuel cells (PEMFCs). In the present era, an extensive array of polymers and polymer-blended membranes have been scrutinized for their applicability in this domain. Each of these materials presents a set of advantages and disadvantages. However, the realm of PEMFCs is still in search of the perfect membrane endowed with distinct properties. Graphene oxide, a two-dimensional substance arising from the oxidation of graphite, has manifested itself as a promising candidate. Oxygen (O) functional groups are incorporated within the sp² carbon (C) plane of the oxidized graphite, forming graphene oxide. This material can be synthesized by exfoliating graphite oxide, a three-dimensional carbon-based compound, into layered sheets using ultrasonic or mechanical agitation. The presence of multiple reactive oxygen functional groups renders graphene oxide suitable for a diverse array of applications, such as composite polymers, energy conversion materials, environmental safeguards, sensors, transistors, and optical components. This versatility is attributable to its outstanding electrical, mechanical, and thermal properties. Among the various methodologies for graphene oxide synthesis, the modified Hammer method stands out for its simplicity, cost-effectiveness, and high yield. This research delves into the structural analysis of graphene oxide obtained through the Hammer method, utilizing commercially available graphite. The study involves the creation of membranes based on carboxymethylcellulose (NC) that integrate dispersed graphene oxide (GO) sheets. These novel membranes, as well as pristine graphene oxide, were subjected to a comprehensive array of analytical techniques including XRD, XPS, Raman, FTIR, and SEM microscopy. Additionally, electrophysical characterizations were undertaken employing electrochemical impedance spectroscopy (EIS) measurements. The investigation uncovered that the introduction of NC into the graphene oxide matrix significantly enhances the electron conductivity of the composite membrane. Simultaneously, the presence of graphene oxide contributes to the mechanical robustness and thermomechanical stability of the membrane structure. The principal impetus behind this article lies in furnishing vital insights into the physical and structural attributes of graphene oxide membranes relevant to their deployment in hydrogen energy applications.