Maghemite nanoparticles decorated semiconducting graphitic carbon nitride hetero-structured nanocomposite: Facile synthesis, characterizations and its visible light active photocatalytic system for removal of hazardous organic pollutants from aqueous solutions

Abstract

Hetero-structured nanocomposite consisting of graphitic carbon nitride host, decorated by γ-phase iron oxide, maghemite (γ-Fe2O3@G-CN) was synthesized in different mass contents of γ-Fe2O3 (5%, 10% and 20%) in the composite, by the method of nanosecond pulsed laser fragmentation, and defect engineering in liquid for the removal of hazardous organic pollutants from aqueous solutions. The elemental, structural, and morphological characterizations of the synthesized nanocomposites by XPS, XRD, TEM, and HR-TEM exhibited the proper anchoring of γ-Fe2O3 on the graphitic carbon nitride polymeric network. Also, the diffuse reflectance spectra, and the room temperature photoluminescence spectra respectively revealed that the presence of γ-Fe2O3 in graphitic carbon nitride brought about the enhanced and extended visible light absorption, and reduced recombination of photo induced electron hole pairs, the characteristics desired in a good photo-catalyst. Moreover, this composite material exhibited the z-scheme photo catalytic mechanism, where the more energetic electrons and holes in the composite band structure mediate the redox reaction in the photo-catalysis. The photo-catalytic efficiency of γ-Fe2O3@G-CN nanocomposite was evaluated in the photo-catalytic degradation of methyl blue (MB), and rhodamine-B (Rh-B) cationic dyes under visible light irradiations. For both the degradation processes, all the variants of γ-Fe2O3@G-CN nanocomposite consistently showed the enhanced photocatalytic efficiency with respect to pure GCN, with the maximum efficiency recorded for 10% γ-Fe2O3 in γ-Fe2O3@G-CN nanocomposite.