Enhanced Wide Spectrum Photocatalytic Activity by in-Situ Magnetite-Graphite Nanoplatelets Heterostructure

Abstract

A UV, visible and NIR range irradiation responsive magnetite/graphite nanoplatelets composite was successfully synthesised via a single-step facile in-situ electrochemical exfoliation method using natural vein graphite. The spectral analysis revealed that as-synthesised photocatalyst could rapidly degrade the organic dyes with 96.1, 78.0 and 82.6 % efficiency in 120 minutes under respective UV, Visible, and NIR ranges of the electromagnetic spectrum. The formation of the magnetite-graphite nanoplatelet (GNP) nanocomposite was verified with X-ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) analysis. The scaffold of highly electrically conductive GNP helps magnetite nanoparticles for the efficient distribution of photoinduced electrons generated by the photocatalytic activity to participate in the photodegradation of organic dyes, through rapid superoxide radical formation. The current work presents a hypothesized mechanism for the photocatalyst composite synthesis, while a thorough discussion was made on the improvements in photocatalytic degradation kinetics under multiple irradiation conditions through the synergy of the magnetite and GNP. High efficiency, low-cost facile synthesis, easy up scalability, and the easy removal of the catalyst as needed via an external magnetic field can be identified as major benefits of as-synthesised green catalyst, which can be readily used in dye pollutant removal and wastewater treatment applications.

Keywords

• Magnetite graphite nanoplatelets
• electrochemical synthesis
• photocatalysis
• dye pollutants
• wastewater treatment