Silver-Decorated Cobalt Ferrite Nanoparticles Anchored onto the Graphene Sheets as Electrode Materials for Electrochemical and Photocatalytic Applications

Abstract

The present work describes the synthesis of Ag-CoFe2O4/rGO nanocomposite as a photocatalyst through the hydrothermal process by the attachment of silver and cobalt ferrite (CoFe2O4) nanoparticles on the surface of reduced graphene oxide. The effect of Ag and reduced graphene oxide (rGO) on the structure, optical, magnetic, photocatalytic, and electrochemical performance of the CoFe2O4 is systematically explored through various analytical techniques. The analyses of the observed outcomes reveal that the graphene sheets are exfoliated and decorated with well-dispersed Ag and CoFe2O4 nanoparticles. UV–vis spectra indicate a gradual shift in the absorption edge toward the higher wavelength with the addition of Ag ions, which signifies variation in the energy gap of the samples. Photoluminescence results divulge that graphene can decline the electron–hole recombination rate and improve the photocatalytic activity of the Ag-CoFe2O4/rGO nanocomposite. In this context, the Ag-CoFe2O4/rGO sample presents good catalytic activity as compared to the CoFe2O4 and Ag-CoFe2O4 photocatalysts for the degradation of methylene blue (MB) dye and suggests that the rGO plays a vital role in the Ag-CoFe2O4/rGO nanocomposite. The deterioration rate of the samples is found to be in the order of CoFe2O4(78.03%) < Ag-CoFe2O4(83.04%) < Ag-CoFe2O4/rGO­(93.25%) in 100 min for MB dye, respectively, under visible-light irradiation. The room-temperature ferromagnetic behavior of the samples is confirmed by the M–H hysteresis loop measurements. Overall, the Ag-CoFe2O4/rGO nanocomposite promises to be a strong magnetic photocatalyst for contaminated wastewater treatment. The electrochemical performance of all of the samples was examined by the cyclic voltammetry (CV) that exhibits a superior rate performance and cycle stability of the Ag-CoFe2O4/rGO nanocomposite as compared to the other samples.

High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution

“…Further, Figure c depicts a representative TEM image of the CZ2 sample, which signifies spherical nanoparticles with sizes in the range of 5–9 nm. The periodic lattice fringe spacing of 0.29 nm corresponding to the (220) plane of the spinel ferrite structure can be noticed in Figure d …”

“…The periodic lattice fringe spacing of 0.29 nm corresponding to the (220) plane of the spinel ferrite structure can be noticed in Figure 4d. 60 Furthermore, a typical TEM image of the CZ3 sample is shown in Figure 4e, which represents spherical nanoparticles with sizes in the range of 3−6 nm. The distinct lattice fringes with a spacing of 0.25 nm corresponding to the (311) planes of cubic spinel ferrite can be observed in Figure 4f.…”

One-Pot Synthesis of SnO2-rGO Nanocomposite for Enhanced Photocatalytic and Anticancer Activity

“…The presence of C=O and C-O at the 1713.96 and 1048.37 cm −1 bands indicate the reduction of GO into rGO [ 46 ]. Moreover, O-H stretching vibrations were observed at 3433.69, 1646.43, and 1353 cm −1 for both SnO 2 NPs and SnO 2 -rGO NCs due to the existence water molecules during the hydrothermal process [ 47 ]. The band observed at 593 cm −1 was assigned to the O-Sn-O stretching mode in the SnO 2 NPs [ 48 ], while two strong peaks at 530.20 and 608.6 cm −1 in the SnO2-rGO NCs were assigned to Sn-O stretching vibration owing to the strong interaction between SnO2 and rGO [ 49 ].…”

Magnetic Metal Oxide-Based Photocatalysts with Integrated Silver for Water Treatment

“…Improvements in photocatalytic pollutant removal efficiency arising from silver integration onto magnetic materials are also evident in the case of pharmaceutical pollutants such as tetracycline [69] and sulfanilamide [70]. The silver addition has been proven to enhance the photocatalytic degradation and antibacterial action, not only under UV but under visible illumination as well [10,20,46,62,66,68], even when the base materials are not especially effective under these conditions [20]. In summary, the combined attributes of magnetic materials and silver lead to significantly enhanced composites with usage flexibility.…”

“…In a recent work, Ibrahim et al (2022) observed significantly enhanced photocatalytic pollutant removal efficiency after silver integration for their best TiO 2 /g-C 3 N 4 /Ag sample in both oxidation (azo-dyes/pharmaceuticals) and reduction (Cr 6+ and 4-nitrophenol) processes [61]. Composites with magnetic materials and silver have been proven to be especially efficient in the treatment of heavy metal pollutants, such as Cr 6+ [20] or organics such as methylene blue [10,62,63], rhodamine B [10,46,64,65], malachite green [63,66] and phenol [63,67], along with the photocatalytic neutralization of bacteria such as Escherichia coli [63,68] and Micrococcus luteus [63]. Improvements in photocatalytic pollutant removal efficiency arising from silver integration onto magnetic materials are also evident in the case of pharmaceutical pollutants such as tetracycline [69] and sulfanilamide [70].…”