Probing analysis of Cu-doping on the structural, optical, morphological and magnetic properties of hematite nanoparticles and their antibacterial activity

The present study describes the synthesis of pure and Cu doped α-Fe2O3nanoparticles (with various concentrations of Copper 1, 3, 6, and 9 wt%) by conventional chemical precipitation technique and examines their structural, morphological, optical, magnetic, and antibacterial capabilities. The XRD pattern of pure and Cu-doped α-Fe2O3 nanoparticles exhibit rhombohedral structure and the estimated crystalline sizes were ranged from 39 to 58 nm. It is discovered that the estimated density dislocations linked to the agglomeration/cluster formations diminish when interstitial vacancies are filled with copper. The obtained bandgap from Tauc's plot, 2.07 eV of pure α-Fe2O3 is found to less than Cu doped α-Fe2O3 nanoparticles (2.9-3.4 eV), due to the structural changes and the tailing of localised states into deep bandgap energy levels. The intense blue emission bands (410-490 nm) arised due to the movement of trapped electrons from the donor level to the valance band and broad green emission bands (522-560 nm) are due to deep level CuO defect to the Fe2O3. The fundamental stretching of Fe-O vibrations and the presence of Cu in prepared samples were identified in FTIR and Raman spectra. SEM micrograph shows the uniform distribution of spherical nanoparticles with size ranged from 39 to 61 nm, which is in good accord with XRD studies. Further, the magnetic characteristics of the pure and Cu-doped α-Fe2O3 samples were assessed using a vibrating sample magnetometer (VSM); the ensuing hysteresis loop of the Cu-doped α-Fe2O3 displays weaker ferromagnetic behaviour. In the present investigations, the disc diffusion technique has been used to examine the antibacterial activity. Thus, the results of antibacterial activities demonstrated that at concentrations of 200 and 500 μg/ml of pure and Cu-doped α-Fe2O3 NPs, the highest zone of inhibition was found against gram (+ve) positive bacteria and was followed by the gram (-ve) negative bacteria's.

Toward Efficient Bactericidal and Dye Degradation Performance of Strontium- and Starch-Doped Fe2O3 Nanostructures: In Silico Molecular Docking Studies

In this study, various concentrations of strontium (Sr) into a fixed amount of starch (St) and Fe2O3 nanostructures (NSs) were synthesized with the co-precipitation approach to evaluate the antibacterial and photocatalytic properties of the concerned NSs. The study aimed to synthesize nanorods of Fe2O3 with co-precipitation to enhance the bactericidal behavior with dopant-dependent Fe2O3. Advanced techniques were utilized to investigate the structural characteristics, morphological properties, optical absorption and emission, and elemental composition properties of synthesized samples. Measurements via X-ray diffraction confirmed the rhombohedral structure for Fe2O3. Fourier-transform infrared analysis explored the vibrational and rotational modes of the O-H functional group and the C=C and Fe-O functional groups. The energy band gap of the synthesized samples was observed in the range of 2.78-3.15 eV, which indicates that the blue shift in the absorption spectra of Fe2O3 and Sr/St-Fe2O3 was identified with UV-vis spectroscopy. The emission spectra were obtained through photoluminescence spectroscopy, and the elements in the materials were determined using energy-dispersive X-ray spectroscopy analysis. High-resolution transmission electron microscopy micrographs showed NSs that exhibit nanorods (NRs), and upon doping, agglomeration of NRs and nanoparticles was observed. Efficient degradations of methylene blue increased the photocatalytic activity in the implantation of Sr/St on Fe2O3 NRs. The antibacterial potential for Escherichia coli and Staphylococcus aureus was measured against ciprofloxacin. E. coli bacteria exhibit inhibition zones of 3.55 and 4.60 mm at low and high doses, respectively. S. aureus shows the measurement of inhibition zones for low and high doses of prepared samples at 0.47 and 2.40 mm, respectively. The prepared nanocatalyst showed remarkable antibacterial action against E. coli bacteria rather than S. aureus at high and low doses compared to ciprofloxacin. The best-docked conformation of the dihydrofolate reductase enzyme against E. coli for Sr/St-Fe2O3 showed H-bonding interactions with Ile-94, Tyr-100, Tyr-111, Trp-30, ASP-27, Thr-113, and Ala-6.

Controlled Synthesis of Hollow α-Fe2O3 Microspheres Assembled With Ionic Liquid for Enhanced Visible-Light Photocatalytic Activity

Porous self-assembled α-Fe₂O₃ hollow microspheres were fabricated via an ionic liquid-assisted solvothermal reaction and sequential calcinations. The concentration of the ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [C₄Mim]BF₄) was found to play a crucial role in the control of these α-Fe₂O₃ hollow structures. Trace amounts ionic liquid was used as the soft template to synthesize α-Fe₂O₃ hollow spheres with a large specific surface (up to 220 m²/g). Based on time-dependent experiments, the proposed formation mechanisms were presented. Under UV light irradiation, the as-synthesized α-Fe₂O₃ hollow spheres exhibited excellent photocatalysis in Rhodamine B (RhB) photodegradation and the rate constant was 2–3 times higher than α-Fe₂O₃ particles. The magnetic properties of α-Fe₂O₃ hollow structures were found to be closely associated with the shape anisotropy.

Sustainable preparation of sunlight active α-Fe2O3 nanoparticles using iron containing ionic liquids for photocatalytic applications

Inspired by the nano-segregation of ionic liquids (ILs) into bi-continuous structures constituting of arrays of ionic and non-ionic components, herein, a new and sustainable strategy for preparation of mesh-like nano-sheet α-Fe₂O₃ nanoparticles and their photo-catalytic activity under sunlight, is presented. For the purpose, metal (iron) containing ionic liquids (MILs), 1-alkyl-3-methylimidazolium tetrachloroferrates, [C_nmim][FeCl₄], (n = 4, 8 and 16), which not only act as precursors and solvents but also as structure directing agents have been used. Thus prepared NPs show MIL dependent structural, photophysical and magnetic properties. The catalytic efficiency of NPs has been tested for the photo-degradation of organic dyes (Rhodamine B) in aqueous solution under sunlight. The NPs are found to exhibit comparable catalytic efficiency under sunlight as compared to that observed under high intensity visible lamplight, without showing a decline in their catalytic efficiency even after 4 catalytic cycles. It is anticipated that the present work will provide a new platform for preparation of sunlight active nanomaterials for photo-catalytic applications with control over the structural and physical properties via varying the molecular structure of MILs.

Inspired by nanosegregation of ionic liquids into bicontinuous structures of arrays of ionic and non-ionic components, we present a new sustainable strategy for preparation of mesh-like nano-sheets of α-Fe₂O₃ nanoparticles and their photocatalytic activity under sunlight.

Colloidal systems of surface active ionic liquids and sodium carboxymethyl cellulose: physicochemical investigations and preparation of magnetic nano-composites

Carboxymethyl cellulose-surface active ionic liquid colloidal formulations for preparation of magnetic nano-composites.

Facile and green one pot synthesis of zinc sulphide quantum dots employing zinc-based ionic liquids and their photocatalytic activity

Zinc-based ionic liquids are found to be suitable candidates for the preparation of ZnS QDs, whose properties depend upon the alkyl chain length of imidazolium.

Facile synthesis of pure phase γ-AlOOH and γ-Al2O3nanofibers in a recoverable ionic liquid via a low temperature route

Mesoporous γ-AlOOH and γ-Al₂O₃with fibrous morphology were successfully synthesized by an ionic liquid ([OMim]Br) assisted low temperature precipitation method using aluminum nitrate and ammonia as aluminum source and precipitant, respectively.