Design and photo-Fenton performance of Graphene/CuS/Fe3O4 tertiary nanocomposites for Rhodamine B degradation

• Published in: Catalysis today Vol. 418; p. 114132
• Main Authors: Matos, Renata, Kuźniarska-Biernacka, Iwona, Rocha, Mariana, Belo, João H., Araújo, João Pedro, Estrada, Ana C., Lopes, Joana L., Shah, Tushti, Korgel, Brian A., Pereira, Clara, Trindade, Tito, Freire, Cristina
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2023
• Subjects: Adsorption; Copper sulfide nanocrystals; Graphene flakes; Graphene hybrid nanostructures; Iron oxide nanoparticles; Photocatalysis; Rhodamine B; Graphene flakes; Iron oxide nanoparticles; Adsorption; Photocatalysis; Copper sulfide nanocrystals; Graphene hybrid nanostructures; Rhodamine B
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2023.114132

This study describes nanocomposites of graphene flakes (GF) combined with CuS, Fe3O4 and CuS−Fe3O4 nanoparticles prepared by wet chemical methods. The Fe3O4 and/or CuS nanoparticles were directly anchored onto GF without requiring additional chemical treatment. The composition, structure and morphology of the nanocomposites, as well as of the pristine GF and metal oxide/sulfide nanoparticles were characterised by X − ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), powder X − ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The results confirmed the successful attachment of CuS nanophases (size range: 23.7–50.1 nm) and/or Fe3O4 nanoparticles (size range: 10.6–15.8 nm). The adsorption and photocatalytic properties of the GF−based nanocomposites were evaluated at room temperature using Rhodamine B (RhB) as a model contaminant. Theoretical models were fitted to the adsorption kinetic results using the pseudo-first-order, pseudo-second-order and Elovich equations, while the adsorption mechanism was determined using the intraparticle diffusion, Bangham and Boyd models. The RhB adsorption efficiency was 6.5% for GF@CuS−Fe3O4 after 180 min contact time, whereas for the other materials was significantly higher: 97.6%, 60.9% and 31.9% for GF, GF@CuS and GF@Fe3O4, respectively. The adsorption capacity of GF and composites fitted the pseudo−second−order kinetic and Elovich models. The influence of the nanostructures composition on the corresponding photocatalytic activity in the degradation of RhB under a 150 W halogen lamp was also evaluated. The GF@CuS−Fe3O4 nanocomposite totally eliminated the dissolved RhB after 60 min irradiation, whereas the GF@CuS, GF@Fe3O4 and pristine Fe3O4 removed 75.6%, 80.9% and 30.8%, respectively, after 180 min irradiation. It was found that the photocatalytic behaviour of the composites was best described by the first−order kinetic model. The rate constant of the photocatalytic RhB removal for GF@CuS−Fe3O4 (k = 7.05 ×10−2 min−1) was 2.1, 5.1 and 15.0 times higher than those obtained for GF@CuS, GF@Fe3O4 and pristine Fe3O4, respectively, after 60 min of visible light irradiation. [Display omitted] •Green and scalable method for the preparation of two- or three-component graphene flakes/CuS/Fe3O4 composites.•RhB adsorption process (31.9–60.9%) is controlled and limited by chemisorption and reaches equilibrium after 30–60 min.•High to excellent dye degradation efficiency (78%−98% in 60 min) under mild reaction conditions.•The three-component composite presented 15 × faster performance than the two-component counterparts.