rGO/MnO₂ nanowires for ultrasonic-combined Fenton assisted efficient degradation of Reactive Black 5

Reduced graphene oxide (rGO) coated manganese dioxide (MnO₂) nanowires (NWs) were prepared by the hydrothermal method. Raman spectra confirmed the presence of rGO and the Brunauer–Emmett–Teller surface area of rGO/MnO₂ NWs was found to be 59.1 m²g⁻¹. The physico-chemical properties of prepared catalysts for the degradation of Reactive Black 5 (RB5) dye were investigated. 84% of RB5 dye in hydrogen peroxide solution was successfully degraded using rGO/MnO₂ NWs, while only 63% was successfully degraded with pristine α-MnO₂ NWs in 60 min owing to the smaller crystallite size and large surface area. Further, the ultrasonic-combined Fenton process significantly enhanced the degradation rate to 95% of RB5 by the catalyst rGO/MnO₂ NWs due to synergistic effects. The decomposition products identified using gas chromatography-mass spectrometry revealed a higher production rate of fragments in the ultrasonic-combined Fenton process. Therefore, rGO/MnO₂ NWs with the ultrasonic-combined Fenton process is an efficient catalyst for the degradation of RB5, and may be used for environmental protection.