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Transition metal centers dispersed over nitrogen-doped carbon (M-NC) supports have been widely explored for electrocatalytic reactions; however, sparsely reported for electrochemical nitrogen reduction reaction (ENRR). Particularly, the single-atom catalysts (SACs) have shown reasonable ammonia yield rate and faradaic efficiency (FE), but their complex synthesis and low durability for long-term electrocatalysis runs restrict their use on a larger scale. Importantly, the catalytic active sites in metal nanostructured-based M-NC catalysts toward enhanced N 2 adsorption and activation are still not clear as they are highly challenging to reveal. A few studies have predicted that the surface oxygen vacancies (O vac ) favor an enhanced ENRR performance. Herein, a strategy using tailored M-NC content and O vac in a single catalyst for enhanced ammonia electrosynthesis is devised. A mesoporous bimetallic spinel oxide (CuFe 2 O 4 ) supported over N-doped carbon (CuFe 2 O 4 @NC) derived from Prussian blue analog (PBA) via controlled pyrolysis possess is found to show boosted ENRR activity. Moreover, operando NH 3 formation over the catalyst is observed using four electrode set up. This approach enables rapid evaluation ofelectrocatalytic efficacy and avoids false positive results. The rotating disc electrode results reveal that mass transport in acidic media and surface absorption in alkline media primarily regulate ENRR over CuFe 2 O 4 @NC electrocatalyst., (© 2024 Wiley‐VCH GmbH.)

Magnetic CuFe 2 O 4 was prepared with the modified sol-gel method and used for enhanced peroxymonosulfate (PMS) activation and ofloxacin (OFL) degradation. The OFL could almost degrade within 30 min at a catalyst dosage of 0.66 g/L, PMS concentration of 0.38 mM, and initial pH of 6.53 without adjustment, using response surface methodology (RSM) with Box-Behnken design (BBD). In the CuFe 2 O 4 /PMS system, the coexisting substances, including CO 3 2- , NO 3 - , SO 4 2- , Cl - and humic acid, have little effect on the OFL degradation. The system also performs well in actual water, such as tap water and surface water (Mei Lake), indicating the excellent anti-interference ability of the system. The cyclic transformation between Cu(II)/Cu(I) and Fe(III)/Fe(II) triggers the generation of active radicals including SO 4 •- , •OH, •O 2 - and 1 O 2 . The OFL degradation pathway, mainly involving the dehydrogenation, deamination, hydroxylation, decarboxylation and carboxylation processes, was proposed using mass spectroscopy. Moreover, the toxicity assessment indicated that the end intermediates are environmentally friendly. This study is about how the CuFe 2 O 4 /PMS system performs well in PMS activation for refractory organic matter removal in wastewater.

The primary purpose of this study was to produce an ore-based high-capacity supercapacitor electrode. For this, chalcopyrite ore was first leached with nitric acid, and then metal oxide synthesis was carried out immediately on nickel foam using a hydrothermal technique from the solution. Cauliflower-patterned CuFe 2 O 4 with a wall thickness of about 23 nm was synthesized on the Ni foam surface, characterized by XRD, FTIR, XPS, SEM, and TEM investigations. The produced electrode also displayed a feature of a battery-like charge storage mechanism with a specific capacity of 525 mF cm -2 at 2 mA cm -2 current density, energy of 8.9 mWh cm -2 , and a power density of 233 mW cm -2 . Additionally, even after 1350 cycles, this electrode still performed at 109% of its original capacity. The performance of this finding is 255% higher than that of the CuFe 2 O 4 in our earlier investigation; despite being pure, it performs far better than some of its equivalents in the literature. Obtaining such performance from an electrode made from ore indicates that the use of ore has a lot of potential for supercapacitor production and property improvement.

In this study, CuFe 2 O 4 ferrite was supported on biochar produced from malt biomass residues as a photocatalyst for degradation of methylene blue (MB), methyl orange (MO), and tartrazine (TZ) dyes. XRD, FT-IR, and FE-SEM were used to characterize the crystallinity and morphology of the samples. The characterization showed that the ferrite was uniformly supported on the surface of the biochar, confirming the formation of the composite. Degradation tests showed that CuFe 2 O 4 degraded approximately 50, 47, and 62% of MB, MO, and TZ dyes, respectively, after 60 min of reaction. On the other hand, the CuFe 2 O 4 /biochar composite showed a significant increase in dye degradation, ~ 100%, for all three dyes. This increase in degradation efficiency may be due to less agglomeration of supported particles and due to decreased recombination of electron/hole pairs. Thus, results showed that the photocatalyst composite produced in this study is an effective alternative for removing dyes from wastewater., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Solar water splitting has emerged as an urgent imperative as hydrogen emerges as an increasingly important form of energy storage. g-C 3 N 4 is an ideal candidate for photocatalytic water splitting as a result of the excellent alignment of its band edges with water redox potentials. To mitigate electron-hole recombination that has limited the performance of g-C 3 N 4 , we have developed a semiconductor heterostructure of g-C 3 N 4 with CuFe 2 O 4 nanoparticles (NPs) as a highly efficient photocatalyst. Visible-light-driven photocatalytic properties of CuFe 2 O 4 /g-C 3 N 4 heterostructures with different CuFe 2 O 4 loadings have been examined with two sacrificial agents. An up to 2.5-fold enhancement in catalytic efficiency is observed for CuFe 2 O 4 /g-C 3 N 4 heterostructures over g-C 3 N 4 nanosheets alone with the apparent quantum yield of H 2 production approaching 25%. The improved photocatalytic activity of the heterostructures suggests that introducing CuFe 2 O 4 NPs provides more active sites and reduces electron-hole recombination. The g-C 3 N 4 /CuFe 2 O 4 heterostructures furthermore show enhanced electrocatalytic HER activity as compared to the individual components as a result of which by making heterostructures g-C 3 N 4 with CuFe 2 O 4 increased the active catalytic surface for the electrocatalytic water splitting reaction. The enhanced faradaic efficiency of the prepared heterostructures makes it a potential candidate for efficient hydrogen generation. Nevertheless, the designed heterostructure materials exhibited significant photo- and electrocatalytic activity toward the HER, which demonstrates a method for methodically enhancing catalytic performance by creating heterostructures with the best energetic offsets.

Microwave-assisted catalytic oxidation technology has become an effective technology for rapid removal of organic pollutants in wastewater. In this research, the removal of methyl orange (MO) from aqueous solution by CuFe 2 O 4 loaded on carbon nanotubes (CuFe 2 O 4 /CNTs) under microwave irradiation was studied. The effects of different loadings (1:2, 1:4, 1:8) of CuFe 2 O 4 on the dielectric loss, magnetic loss, dielectric loss factor, magnetic loss factor, and reflection loss of composite materials were studied. The results showed that the microwave adsorption performance was improved by loading CuFe 2 O 4 on CNTs. These different composites were further characterized by SEM, FTIR, and XRD techniques. In addition, this article also studied the effects of different microwave irradiation time, pH, and ionic factors on the degradation of MO. In particular, the mechanism of MO degradation by composite materials under different pH conditions was also studied in detail. The results showed that the removal rate reaches 97% with 5 min under the best conditions, and the composite material had good anti-interference performance. This study may provide a new option to degrade organic dye in wastewater treating., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Dye wastewater is a serious threat to human health and life. It is an important task for researchers to treat it efficiently. Among many treatment methods, the photo-Fenton method can rapidly degrade organic pollutants. In this study, a ternary photocatalyst, Ag 2 O-NiO/CuFe 2 O 4 , was prepared and applied for a photo-Fenton reaction to degrade methylene blue (MB). MB had the best degradation effect when 10 mg of the catalyst were used in an 80 mL reaction system for measurement. The degradation rate of MB was up to 96.67% in 60 min with a high degradation rate constant k=5.67×10-2min-1. The total organic carbon (TOC) degradation rate was 78.64% with a TOC degradation rate constant of k=2.57×10-2min-1. Therefore, this study fully proves that Ag 2 O-NiO/CuFe 2 O 4 can catalyze the photo-Fenton reaction and effectively degrade MB.

Application of magnetite nanoparticles (CuFe 2 O 4 /GO) were anchored on graphene oxide (GO), as a Heterogeneous nanocomposite for activating of peroxymonosulfate (PMS) into Metronidazole (MNZ) destruction. The effect of solution pH, reaction time, effectiveness of water matrix components and trapping factors, different catalyst concentrations, PMS and contaminants were evaluated as operating factors on the efficiency of MNZ degradation. Also, mineralization, stability, reactivity and Recycling tests of the catalyst, and the degradation kinetics were performed. MNZ degradation and mineralization were obtained under optimal conditions (0.2 g/L catalyst, pH = 5, 30 mg/L MNZ and 2 mM PMS), 100% and 41.02%, respectively over 120 min. Leaching of Fe and Cu was found <0.2 mg/L for CuFe 2 O 4 /GO showed a high stability of catalyst, and a significant recyclability was achieved CuFe 2 O 4 /GO within 5 times consecutive use. MNZ degradation affected by anions was reduced as follows: HCO 3 -  > NO 3 -  > Cl - radicals played a dominant role in the degradation process of MNZ. As a result, the CuFe2O4/GO/PMS system can be described as a promising activation of PMS in MNZ degradation, due to its high stability, reusability and good catalyst reactivity, and the production of reactive species simultaneously.4 2- . The experimental data were very good agreement with pseudo-first-order kinetic model, and during quenching tests SO 4 •- radicals played a dominant role in the degradation process of MNZ. As a result, the CuFe2O4/GO/PMS system can be described as a promising activation of PMS in MNZ degradation, due to its high stability, reusability and good catalyst reactivity, and the production of reactive species simultaneously., Competing Interests: Conflict of interestThe authors of this article declare that they have no conflict of interests., (© Springer Nature Switzerland AG 2020.)

Magnetic nanoparticles (MNPs) are used in a wide range of sectors ranging from electronics to biomedicine, as well as in eutrophicated lake restoration due to their high P, N, and heavy metal adsorption capacity. This study assessed the effects of MNPs on mortality and morphometric changes of D. magna. According to the SEM, the synthesised MNPs were found to have spherical nanoparticles, be uniformly distributed, and have a homolithic size distribution of 50-110 nm. The EDX spectra confirmed the elemental structure and purities of these MNPs. A total of 396 neonates were used for short-term bioassays (96 h) through the MNPs in the laboratory (16:8 photoperiod). Experiments were applied in triplicate for each concentration of CuFe 2 O 4 , CoFe 2 O 4 , and NiFe 2 O 4 MNPs and their respective control groups. Mortality and morphological measurements of each individual were recorded every 24 h. In the probit analysis, the 96-h LC 50 (p < 0.05) for CuFe 2 O 4 , CoFe 2 O 4 , and NiFe 2 O 4 MNPs was calculated to be 1.455 mg L -1 , 39.834 mg L -1 , and 21.730 mg L -1 , respectively. CuFe 2 O 4 MNPs were found to be more toxic than the other two MNPs. The concentrations of CuFe 2 O 4 , CoFe 2 O 4 , and NiFe 2 O 4 MNPs drastically affected life span and morphologic growth of D. magna as a result of a short time exposure. The results of this study are useful for assessing what risks they pose to freshwater ecosystems.

A series of the magnetic CuFe 2 O 4 -loaded corncob biochar (CuFe 2 O 4 @CCBC) materials was obtained by combining the two-step impregnation of the corncob biochar with the pyrolysis of oxalate. CuFe 2 O 4 @CCBC and the pristine corncob biochar (CCBC) were characterized using XRD, SEM, VSM, BET, as well as pH ZPC measurements. The results revealed that CuFe 2 O 4 had a face-centered cubic crystalline phase and was homogeneously coated on the surface of CCBC. The as-prepared CuFe 2 O 4 @CCBC(5%) demonstrated a specific surface area of 74.98 m 2 ·g -1 , saturation magnetization of 5.75 emu·g -1 and pH ZPC of 7.0. The adsorption dynamics and thermodynamic behavior of Pb(II) on CuFe 2 O 4 @CCBC and CCBC were investigated. The findings indicated that the pseudo-second kinetic and Langmuir equations suitably fitted the Pb(II) adsorption by CuFe 2 O 4 @CCBC or CCBC. At 30 °C and pH = 5.0, CuFe 2 O 4 @CCBC(5%) displayed an excellent performance in terms of the process rate and adsorption capacity towards Pb(II), for which the theoretical rate constant (k 2 ) and maximum adsorption capacity ( q m ) were 7.68 × 10 -3 g·mg -1· ·min -1 and 132.10 mg·g -1 separately, which were obviously higher than those of CCBC (4.38 × 10 -3 g·mg -1 ·min -1 and 15.66 mg·g -1 ). The thermodynamic analyses exhibited that the adsorption reaction of the materials was endothermic and entropy-driven. The XPS and FTIR results revealed that the removal mechanism could be mainly attributed to the replacement of Pb 2+ for H + in Fe/Cu-OH and -COOH to form the inner surface complexes. Overall, the magnetic CuFe 2 O 4 -loaded biochar presents a high potential for use as an eco-friendly adsorbent to eliminate the heavy metals from the wastewater streams.

The development of simple, practical and inexpensive catalysis systems using natural materials is one of the main goals of pharmaceutical chemistry as well as green chemistry. Owing to the ability of easy separation of nanocatalyst, those goals could be approached by applying heterogeneous bionanocatalyst in combination with magnetic nanoparticles. Starch is one of the most abundant natural polymers; therefore, preparing bionanocatalyst from starch is very valuable as starch is largely available and inexpensive. An ecologically benign and efficacious heterogeneous nanocatalyst was prepared based on a biopolymer, and its attributes and morphology were specified by using Fourier transform infrared spectra, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermal analysis and vibrating sample magnetometer measurements; followed by studying catalytic behaviour of bionanocomposite in a multicomponent reaction to synthesize of 4H-pyran derivatives. 4H-pyran is extremely valuable in pharmaceutical chemistry, and the development of methods for synthesis of different derivatives of 4H-pyran is momentous. Revealing environmentally benign nature, mild condition, easy work-up, low cost and non-toxicity are some of the advantages of this protocol. Besides, the bionanocomposite was recovered using an external magnetic bar and could be re-used at least six times with no further decrease in its catalytic activity., Competing Interests: We have no competing interests., (© 2020 The Authors.)

Naproxen, a widely used nonsteroidal anti-inflammatory drug, has been detected in many environmental matrixes and is regarded as an emerging pollutant. Sulfate radical (SO 4 · - ) -based advanced oxidation processes have attracted wide attention due to their high efficiency and applicability in the removal of emerging contaminants. In this study, CuFe 2 O 4 was used as an efficient catalyst to activate peroxymonosulfate to oxidize naproxen. The results suggested that 92.3% of naproxen was degraded and 50.3% total organic carbon was removed in 60 min in the presence of 0.3 g·L -1 CuFe 2 O 4 and 2 mM peroxymonosulfate. This degradation system showed strong adaptability in a wide pH range from 4.0 to 10.0. Free radical scavenger experiments and electron spin resonance analysis indicated that 1 O 2 , ·OH, and SO 4 · - are the main active species. Finally, the potential degradation pathways of naproxen were proposed by detecting and analyzing the degradation products with ultra-high-performance liquid chromatography combined with mass spectrometry. The results of this study suggest that the CuFe 2 O 4 -activated peroxymonosulfate system is a promising technology for the removal of naproxen from natural water.

In this work, we reported a facile approach to prepare a uniform copper ferrite nanoparticle-attached graphene nanosheet (CuFe2O4-GN). A one-step solvothermal method featuring the reduction of graphene oxide and formation of CuFe2O4 nanoparticles was efficient, scalable, green, and controllable. The composite nanosheet was fully characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), which demonstrated that CuFe2O4 nanoparticles with a diameter of approximately 100 nm were densely and compactly deposited on GN. To investigate the formation mechanism of CuFe2O4-GN, we discussed in detail the effects of a series of experimental parameters, including the concentrations of the precursor, precipitation agent, stabilizer agent, and graphene oxide on the size and morphology of the resulting products. Furthermore, the electrochemical properties of the CuFe2O4-GN composite were studied by cyclic voltammetry and galvanostatic charge-discharge measurements. The composite showed high electrochemical capacitance (576.6 F·g(-1) at 1 A·g(-1)), good rate performance, and cycling stability. These results demonstrated that the composite, as a kind of electrode materials, had a high specific capacitance and good retention. The versatile CuFe2O4-GN holds great promise for application in a wide range of electrochemical fields because of the remarkable synergistic effects between CuFe2O4 nanoparticles and graphene.

This work is devoted to the systematic study of the optical and magneto-optical properties of sputter deposited CuFe₂O₄ thin films in the photon energy region between 2 and 5 eV using spectroscopic ellipsometry and magneto-optical Kerr spectroscopy. The spectral dependence of both the diagonal and off-diagonal elements of the permittivity tensor is determined. A complete picture about the electron transitions in CuFe₂O₄ is suggested in the frame of intervalence charge transfer and intersublattice charge transfer transitions. The effect of deposition conditions and post-deposition treatment in CuFe₂O₄ films upon the optical and magneto-optical properties is discussed.