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... means that the minimum energy of the lowest conduction band is just above the maximum energy of the valence band at the same crystal momentum. If this is not, it is called the indirect band gap energy, as shown in Figure 1 below. The UV-Visible diffuse -reflectance spectrophotometer is a viable tool for the use of a simple method based on the Kubelka-Munk theory [30] and the Tauc [31] plot to obtain the band gap energy. ...
Citations
... Plot of (αhv)2 versus hv (photon energy) of nickel-substituted cobalt ferrite nanoparticlesThis phenomenon occurred due to a decrease in the lattice parameter of these nickel-substituted cobalt ferrite nanoparticles. The findings of CoFe2O4 and NiFe2O4 are consistent with Situmeang et al.[42] and ...
Nanoparticle technology is fast progressing and is being employed in innumerable medical applications. At this time, the public's health is seriously threatened by the rise of bacterial strains resistant to several medications. Metal nanoparticles are a potential alternate approach for tackling this global concern, and this is the main focus of this study. The citrate precursor sol-gel synthesis method was used to synthesize the, Ni_x Co_(1-x) Fe_2 O_4, (where x = 0.0:0.2:1.0) nanoparticle. XRD identified the development of the cubic crystal structure to have a preferential orientation along (311), and the average particle size was found to be 29-38 nm. The average crystallizes assessed with ImageJ software and origin 22 of the SEM are nearly identical to the XRD results. In the created NCF NPs, the FT-IR spectroscopy reveals structural examinations and the redistribution of cations between octahedral (505-428 cm-1) and tetrahedral (653-603 cm-1) locales. Finally, the decrease of coercive fields HC, 2384 Oe to 241.93 Oe replacement of Co2+ cation with Ni2+. Band gap energy rises as Ni concentration increases, which may be attributed to the fact that the ionic radii of Ni2+ ions are smaller than that of Co2+ ions, which results in a strong electrostatic interaction. On the contrary, except at x = 0.4, the dielectric constant decreases as the nickel concentration increases. According to the findings of this research work, nanoparticles composed of Ni_0.4 Co_0.4 Fe_2 O_4 have demonstrated a promising value against S. aureus and E. coli, and it suggests a proposed model for their potential use as a new source of antibacterial agent.
... These peaks signify interactions involving the 3d Ni 2+ orbitals with the 2p O 2orbitals, specifically indicating d-d transitions in Ni 2+ ions within an octahedral coordination geometry. In this geometry, the intra-atomic d-d transitions exhibit lower intensity compared to inter-atomic transitions in the region of the fundamental absorption edge [75]. The 3A 2 g →3 T 1 g (P) and 3A 2 g →3 T 1 g (F) transitions of Ni 2+ ions in octahedral geometry are observed within the wavelength ranges of 900-500 nm and 550-370 nm, respectively [76]. ...
Novel 0D Ni3V2O8 quantum dots (QDs) were decorated on the ultra-thin 2D g-C3N4 nanosheet (UCN) using a
hydrothermal approach. The embedded Ni3V2O8 QDs play a dual role by trapping charge carriers, promoting
electron-hole separation, and forming a p-n S-scheme heterojunction, improving the redox potential of the
electrons and holes for surface reactions. HR-TEM analysis confirmed that Ni3V2O8 QDs with a size varying
between 3 to 5 nm have intimate contact with the UCN surface. XPS and ESR spin-trapping agents experiment
confirmed the formation of S-scheme heterojunctions between Ni3V2O8 QDs and UCN. Photocurrent and PL
spectra indicated the synthesized heterostructures have high charge carrier transportation and lower recombination
rates. The optimum Ni3V2O8 QDs/UCN heterostructure showed the highest photocatalytic hydrogen
evolution activity, about 14 times higher than that of pristine UCN. This remarkable improvement in activity can
be ascribed to the synergy effect of the S-scheme charge pathway mechanism and the improved light absorption
facilitated by the Ni3V2O8 quantum dots. As a result, these factors effectively accelerate the migration and
transportation of photoinduced charge carriers, offering increased active sites for the H2 generation process. This
study emphasizes the importance of a well-designed interfacial heterojunction to achieve enhanced photocatalytic
performance.
... These peaks signify interactions involving the 3d Ni 2+ orbitals with the 2p O 2orbitals, specifically indicating d-d transitions in Ni 2+ ions within an octahedral coordination geometry. In this geometry, the intra-atomic d-d transitions exhibit lower intensity compared to inter-atomic transitions in the region of the fundamental absorption edge [75]. The 3A 2 g →3 T 1 g (P) and 3A 2 g →3 T 1 g (F) transitions of Ni 2+ ions in octahedral geometry are observed within the wavelength ranges of 900-500 nm and 550-370 nm, respectively [76]. ...
... To remove the above-mentioned issues, spinel ferrites have aroused much curiosity recently due to their potential involvement in many redox reactions, strong electrochemical stability, and pseudocapacitive activity [49][50][51][52][53][54]. In terms of theoretical capacity and operating voltage, spinel ferrites outperforms the other metal oxides [55]. NiFe 2 O 4 is a spinel ferrite that might been used as material for anode inside supercapacitors and (lithium-ion batteries). ...
... This shows the ionic resistance of the electrolyte, the inherent resistance of the electrode material, the contact resistance between the electrode material and the current collector. Rct was estimated to be 0. 55 Figure 6b shows that the CuS 2 /NiFe 2 O 4 nanocomposite's current density is very stable after 45 hours. The CV polarisation curve was used to study the CuS 2 /electrocatalytic NiFeO 4 's properties. ...
Spinel ferrites have lately gained popularity owing to their unique properties like high electrochemical stability, redox states & pseudocapacitive activity for supercapacitors applications. In present study, firstly rationally designed CuS2/NiFe2O4 nanostructure is fabricated using a simple and efficient single step hydrothermal route. The resultant CuS2/NiFe2O4 outperforms the capacitance efficiency of the CuS2 and NiFe2O4 due to the synergistic effect. The CuS2/NiFe2O4 nanocomposite responses greater specific capacitance of 1329.54 F g−1 at 1.0 A g−1, & nanocomposite electrode employed more than 96.21% of its capacitance around 5 A g−1 even after 5000 cycles. Hence, electrochemical efficiency could be boast up by tailoring in the morphology, surface interfaces and creation of oxygen vacancy. Therefore, this hybrid material might also be employed for water splitting catalysts, Na-ion hybrid capacitors, and other difficult energy storage and conversion devices.
... The calculation of bandgap energy of all nanocatalysts has been carried out by the Tauc equation (more details of the equation are explained in supporting information) [37,[62][63][64][65]. As the CB and VB levels of Bi 2 O 3 (E CB = + 0.8 eV, E VB = + 3.2 eV) are, respectively, more positive than those of CdS (E CB = − 0.2 eV, E VB = + 2.0 eV) [45], both type-II and Z-scheme heterojunction mechanisms can be used to explain the charge transfer route between Bi 2 O 3 and CdS. ...
Paracetamol (PCM) and diclofenac (DCF) are extensively used analgesic and antipyretic drugs over the counter. Their increasing levels in water bodies cause serious environmental concerns and demand their removal by an advanced technique involving cost-effective and highly efficient nanomaterials. Herein, great efforts were made to produce a natural Z-scheme-type bismuth oxide-coupled cadmium sulfide (Bi2O3@CdS) nanocomposite using Azadirachta indica aqueous leaves extracts. The unique morphology, crystalline structure, coupling, and bonding of Bi2O3@CdS nanocomposite were characterized by X-ray powder diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence emission spectroscopy (PL) technologies. Subsequently, photocatalytic performances were evaluated by degradation of PCM (98%) and DCF (96%) after 240 min, at an optimum dose and neutral pH, from simulated water under daylight through a spectrometer. The degradation of PCM and DCF on Bi2O3@CdS followed the first-order kinetics with about 3.2 and 2.5 times apparent rate constants that of individuals, respectively. The improved photocatalytic activity exhibited by Bi2O3@CdS is attributed to a synergistic effect including high surface activity (63.17 m2 g−1), porosity (1.53 nm), and low bandgap (2.0 eV), strong light absorption (λ = 502 nm), matched energy band structure, and the improved separation of photogenerated charge carriers between the individual's nanoparticles. The photogenerated reactive species as electrons (eCB−), holes (hVB+), and hydroxyl (•OH) radicals in the Z-scheme mechanism refer to the directed migration of photoinduced carriers in photocatalysis. Thus, it can be suggested that Bi2O3@CdS is a sustainable (reusability up to n = 10) and promising photocatalyst for environmental purification and clean energy utilization.
