Comparative analysis of graphene oxide (GO) reduction methods: impact on crystallographic, morphological, and optical properties

This study presents a comprehensive investigation into the crystallographic, morphological, and optical characteristics of reduced graphene oxide (rGO) synthesized through two distinct methodologies, namely modified Hummers method (MHM) and electrochemical exfoliation (EE) method. Through XRD analysis, it was revealed that rGO_E exhibited a notable diffraction peak at 2θ = 26.52°, corresponding to the (002) plane with an interlayer distance (d-spacing) of 3.5 Å, while rGO_H displayed sharp peaks at 11.30° ((001) plane of graphene oxide) and 24.96° ((002) plane of rGO). The SEM investigation revealed distinctive morphological differences, with rGO_E showcasing a crumpled, interconnected, paper-like structure, in contrast to rGO_H produced via the modified Hummers method. Furthermore, FTIR analysis highlighted the diverse chemical moieties in both rGO_E and rGO_H, reflecting the unique chemical transformations associated with each synthesis route. Significantly, UV–vis is absorbance spectra indicated a redshift in rGO_H compared to rGO_E, indicative of an increased electron concentration resulting from the partial restoration of sp² carbon bonds during reduction. Crucially, the investigation demonstrated that the synthesis method significantly influences rGO properties, with rGO_H possessing a larger specific surface area (552.36 m²/g) compared to rGO_E (110.16 m²/g). These findings underscore the importance of selecting the appropriate synthesis method to tailor rGO’s crystallographic, morphological, and optical properties for specific applications, thus advancing our understanding and utilization of this versatile carbon-based material.