Enhanced Electrochemical Degradation of Methylene Blue Using Sb/Sb₂O₃ Nanoparticles Decorated on Reduced Graphene Oxide

The degradation of methylene blue (MB), a persistent and environmentally harmful textile dye, was investigated electrochemically using an antimony/antimony oxide–reduced graphene oxide (Sb/Sb2O3-rGO) composite. This study explores the chemical synthesis and characterization of Sb/Sb2O3-rGO using various microscopic, structural, spectroscopic, and electrochemical techniques. Accordingly, scanning electron microscopy (SEM) analysis exhibited the electrocatalyst in a nanosheet template of rGO coated with Sb/Sb2O3, having a size of ∼50 nm, and high-resolution transmission electron microscopy (HR-TEM) unveiled a porous, rough surface that provides high surface energy, a polycrystalline nature, and a defective structure, having d-spacing for Sb ∼0.24 nm and for Sb2O3 is 0.36 nm. X-ray diffraction (XRD) studies revealed the presence of the senarmontite phase of Sb/Sb2O3, while X-ray photoelectron spectroscopy (XPS) analysis confirms the existence of antimony in both Sb(0) and Sb(+3) oxidation states, having a ratio of 4:1 with O incorporation. Raman spectra supported the presence of defect-induced broadening in the D-band; also, the ID/IG ratio is 1.16. Thermogravimetric (TG) analysis attested to the catalyst’s high stability, up to 50% more than rGO and 25% more stability than Sb2O3 NPs. BET surface area analysis showcased its surface area of 300 m2g–1 and mesoporous nature, having a pore size of ∼70 nm. UV–vis and FTIR spectral analyses provided evidence of the bonding of Sb/Sb2O3-rGO. The electrochemical studies reveal the catalytic behavior, degradation mechanism, and reaction kinetics of MB dye on Sb/Sb2O3-rGO were systematically examined from cyclic voltammetry (CV) at an ultralow potential of 0.17 V vs SCE, linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (i–t), having stability extended up to 9 h and cyclic stability up to 3000 cycles. Furthermore, degradation analysis was conducted using UV–vis and FTIR spectroscopic techniques, revealing the complete degradation of the dye. This study provides valuable insights into the use of non-noble metals for wastewater remediation, with a focus on complete dye degradation.