Synthesis and characterization of sulfanilic-acid mediated by ZnO/Graphene oxide composite with preliminary electrochemical assessment

This study presents a simple co-precipitation method for a ternary composite integrating zinc oxide (ZnO), sulfanilic acid (SA) and graphene oxide (GO). Sulfanilic acid serves a dual role as a molecular linker and structural spacer, enabling uniform anchoring of ZnO nanoparticles onto GO sheets and preventing agglomeration. X-ray diffraction (XRD) revealed phase-pure hexagonal ZnO and partial ordering in GO. Raman spectroscopy confirmed the presence of distinct D and G bands, along with strong π–π stacking interactions, suggesting good integration of the carbon framework. X-ray photoelectron spectroscopy (XPS) provided evidence of N–Zn coordination and hydrogen bonding between sulfonic (S = O) and hydroxyl (H–O–Zn) groups, indicating successful chemical interactions at the interface. FTIR spectra further supported this by revealing characteristic peaks corresponding to amine and sulfonic acid functionalities. Preliminary electrochemical evaluation via cyclic voltammetry and impedance spectroscopy in 1 M NaOH revealed capacitive behavior, suggesting potential for further optimization toward energy storage applications. A ternary nanocomposite (ZnO/GO/SA) was synthesized via simple co-precipitation method. SEM confirmed uniform dispersion of ZnO nanoparticles anchored on GO sheets with reduced agglomeration. XPS revealed N–Zn coordination and hydrogen bonding between sulfonate groups and ZnO, confirming chemical integration. FTIR spectra further supported this by revealing characteristic peaks corresponding to amine and sulfonic acid functionalities. Raman spectra showed strong π–π interactions and charge transfer between ZnO, GO, and sulfanilic acid.