Lanthanum Ferrite Research Articles

Perovskite-structured LaFeO3 gas sensor modified by polyoxometalate electron acceptor with high sensitivity and low detection limit for acetone gas☆

Lanthanum ferrite is a representative perovskite-structured rare earth-based bimetallic oxide, which has been widely studied in magnetic materials, sensors, catalysts and batteries. Herein, we designed and prepared polyoxometalate electron acceptor decorated LaFeO3 gas-sensitive composite materials with one-dimensional nanoribbons morphology by electrospinning. The effects of different mass fraction of Keggin type phosphotungstic acid (PW12) on the gas-sensitive properties of LaFeO3 nanoribbons were investigated. The results show that the response value of LaFeO3/PW12 sensor to acetone gas first increases and then decreases with the increase of PW12 content. The LaFeO3/3%PW12 sensor exhibits a maximum response of 3.35 to 5 ppm acetone at 250 °C, a 2.6 times increase in response value and a 90 °C reduction in operating temperature compared to pure LaFeO3 nanoribbons. The LaFeO3/3%PW12 sensor exhibits good linear relation in ppb-level concentrations and the lowest detection concentration is 100 ppb. The sensors also show good repeatability in 6 tests and excellent long-term stability in 30 d. The improvement of the gas sensitive properties of the composite can be attributed to the synergistic effect between the two components. As an electron acceptor, PW12 promotes carrier migration between PW12 and LaFeO3, thereby improving the gas sensing performance of LaFeO3. This work promotes the practical application of polyoxometalate to promote rare earth-based gas sensitive materials in sensing field.

Highly sensitive and selective rGO-LaFeO3 nanocomposite based formaldehyde sensors towards air quality monitoring

Formaldehyde (HCHO), a ubiquitous volatile organic compound and recognized human carcinogen, is extensively used in industrial applications such as resin and adhesive production. Even minimal exposure to HCHO can induce serious health effects, including respiratory distress and dermal irritation. Thus, the advancement of highly sensitive and selective sensors for HCHO detection is imperative for safeguarding environmental and indoor air quality. Herein, we report the development of a very sensitive, highly selective, and stable HCHO sensor based on reduced graphene oxide (rGO) and lanthanum ferrite (LaFeO3). LaFeO3 and rGO-LaFeO3 nanocomposites with different compositions were synthesized through an affordable and straightforward sol-gel process. Among them, the LFGO(50:1) sensor demonstrated the highest response and selectivity towards HCHO, with a detection limit (theoretically) as low as 19 ppb (1.5 fold). Notably, it exhibited approximately 15-fold p-type response to 1 ppm of HCHO, while operating at 260°C. The sensor also showed quick response and recovery times of around 1.5 seconds and 36 seconds, respectively while having negligible response to other VOCs, including ethanol, methanol, and NH3. A synergistic effect of rGO and LaFeO3 is attributed to this improved sensing behavior. rGO offers a large surface area that facilitates the adsorption of HCHO molecules, while LaFeO3 acts as a catalyst for the oxidation of HCHO. The sensor also showed good selectivity, stability, and reproducibility, making the material a promising candidate for practical applications towards environment monitoring, indoor air quality control, and industrial safety.

Synergy of reduced graphene oxide composites with cerium doped lanthanum ferrite for high frequency (12.4–18 GHz) electromagnetic shielding application

In this paper, electromagnetic shielding properties of reduced graphene oxide (RGO) composites with cerium-doped lanthanum ferrite, La0.9Ce0.1FeO3 (LCFO), are studied. The synthesis procedure adopted is incipient wetness impregnation with SBA-15 as a template for LCFO and modified Hummer's method for graphene oxide (GO). The composites are synthesized by in-situ reduction of GO in the presence of LCFO, which acts as a magnetic filler in the weight ratios 1:0, 1:1, 2:1, 3:1 and 1:2 of LCFO and GO. X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and nitrogen absorption/desorption isotherm are used to investigate the structural properties. Vector network analyzer (VNA) is used to ascertain the shielding and dielectric properties. The La0.9Ce0.1FeO3-reduced graphene oxide (LCFG31) composite shows appreciable electrical conductivity of 81.43 S/m and an effective BET surface area value of 23.93 m2g-1. It attenuates >99.99 % of electromagnetic waves, and a shielding effectiveness (SE) value of 41.82 dB at a thickness of 2.36 mm in the Ku frequency band (12.4–18 GHz) has been achieved. The heterogeneous interfaces in the composite structure result in orientational and space charge polarization. The inclusion of magnetic ferrite as filler in composite incurs eddy current loss and magnetic losses. All these factors collectively make the composite material a good choice for electromagnetic shielding which can be further used for commercial applications.

EFFECT OF ANNEALING DURATION ON PHOTOCATALYTIC PROPERTIES OF LaFeO3 PEROVSKITE

In this paper, the effect of the annealing duration on the photocatalytic properties of lanthanum ferrite perovskite synthesized by the hydrothermal method is investigated. Lanthanum ferrite was chosen as the object of study due to its high activity under the influence of visible light. During the experiments, the structural changes occurring in the material during annealing during 2, 4 and 6 hours were studied. The main attention was paid to the analysis of the morphology of nanoparticles, phase composition, crystallinity, absorption spectra and photocatalytic activity. The results show that an increase in the annealing time leads to an improvement in the crystal structure, an increase in the size of crystallites and a higher level of oxygenation. The optimal annealing time to achieve maximum photocatalytic activity was determined to be 6 hours. The work confirms the prospects of using long-term annealing to improve the photocatalytic properties of perovskite-based materials.

Sol-gel synthesis of LaFeO3 perovskite oxide for distinct ridges detection of level II and III latent fingerprints

Latent fingerprints are considered a primary source of best reference for personal identification in criminal investigations. However, poor resolution, less background hindrance, and sensitivity over fingerprint ridges are often problems in fingerprint development. To address these issues, special care is required by developing new fluorescence materials. As a result, this effort was made to synthesize lanthanum ferrite (LaFeO3) fluorescent nano perovskite oxide by the sol–gel method using glycine as fuel, to detect three (I, II, and III) levels of fingerprints. In addition, the absorption spectrum was recorded in a dispersed medium, and dual peaks at 329 and 406 nm in visible regions were obtained, followed by the photoluminescence spectra that showed a broad peak at 527 nm with chromaticity coordinates. Powder X-ray diffraction confirms the synthesized LaFeO3 orthorhombic phase with a crystallite size of 54 nm, and the morphology of LaFeO3 was found to be highly monodisperse. X-ray photoelectron spectroscopy confirmed that La has + 3 with Fe + 3 oxidation states, and Infrared spectroscopic techniques revealed all functional groups were present uniformly. The powder dusting method was applied on various porous and non-porous surfaces, revealing distinct ridges of fingerprints without background hindrance and with precise sensitivity; this proves LaFeO3 is suitable for forensic science.

Clove oil mediated combustion method synthesised Dy stabilized lanthanum ferrite its application as photocatalyst and antibacterial agent

The work gives the details about the influence of Dy substitution in the Lanthanum ferrite (x = 1 mol%, 3 mol%, 5 mol%, 7 mol%) nanoparticles prepared by biofuel mediated combustion method. The studies of PXRD, SEM, UV-DRS, FTIR, TEM were carried out to understand the structural characteristics. The PXRD shows the high crystalline peak of lanthanum ferrites. From Rietveld refinement analysis confirms orthorhombic structure. The estimated crystal size is 31–43 nm. The band gap from UV -DRS studies was in the 2.4–2.8 eV range. The morphological studies SEM and TEM shows the agglomerated structure. The variation of peak intensity (PXRD), the band gap and the force constant calculated from FTIR confirms the presence of dopant in the host disturbed the crystal lattice. The Photocatalytic degradation for the Eosin Y dye were done under visible light. The 3 mol% Dy doped Lanthanum ferrite shows enhanced results of about 85.09 % in 60 min. The crystallinity nature from XRD and band gap of about 2.4 eV could more most supportive parameters for the nanomaterial for photodegradation. The antibacterial activities for E.coli and P. aeruginosa shown effective activity, which could make the sample to be more applicable towards biomedical field.

Lanthanum ferrite modified filling materials and its enhancement for phosphorus and COD removal: Performance and mechanism

Previous studies have developed numerous adsorption composite materials demonstrating substantial removal efficiencies for phosphorus (P) and chemical oxygen demand (COD). However, most of materials targeted single contaminant and were inconvenient to apply in real water bodies owing to size limitation. In the current study, three composite materials‑lanthanum ferrite-modified Quartz balls/Maifan stones/Honeycomb ceramics-were synthesized using one step co-precipitation method. Structural and morphological changes of pre- and post-adsorption were examined through Scanning Electron Microscope - Energy Dispersive Spectrometer (SEM-EDS) and X-ray diffraction (XRD). Kinetics, thermodynamics, and isotherm models were simulated for the analysis of P and COD adsorption. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were employed to elucidate the adsorption mechanisms. The results demonstrated that these materials achieved P maximal removal rate of 99.56 % and COD maximal removal rate up to 94.82 %. The second-order kinetic model for P adsorption was more excellent than that of the first-order model, and the intra-particle diffusion model more accurately described the COD adsorption. Both the Langmuir and Freundlich were used to fit the adsorption isotherm data for P and COD. XPS and FTIR revealed that the adsorption mechanisms for P were ligand exchange and chemical precipitation. Whereas the adsorption mechanisms for COD were ligand exchange and physical adsorption. The materials in the actual farmland drainage performed excellent and effectively reduced the concentration of P and COD up to 68.58 % and 53.98 %, respectively. The lanthanum ferrite-modified fillers provide accessible, universal and bifunctional option for controlling agricultural non-point source pollution.

Green fuel mediated Europium doped Lanthanum ferrites Synthesis, characterisation of and their application as photocatalyst and antibacterial agents

The focus of multiapplication of the nanomaterial is the recent research. Based on that the current work describes synthesis of nano Lanthanum ferrites doped with Europium (1 mol, 3 mol, 5 mol and 7 mol%) by cost effective biofuel combustion method, using Ocimum tenuiflorum extract as fuel. The doping possibly changed the size and morphology of the host as evident from results of XRD, SEM and TEM analysis. As there is increase in band gap from 2.2 to 2.5 eV for undoped to 5 mol% doped Europium which strongly supports the photocatalytic degradation of Congo Red dye in the UV and visible light. The 5 mol% doped Eu shows 65 % and 81 % in UV-light and Visible light respectively. The electrochemical studies indicates the accepted capacitance and semiconductor nature of synthesised nano ferrites. The antibacterial activity was tested against Escherichia coli and Staphylococcus aureus showed 5 mol% Eu doped LFO was more effective than other synthesized LFO.

Improved multiferroic properties of lanthanum ferrites through cobalt doping

LaFeO3 is a type II multiferroic material which exhibits improper ferroelectricity induced by magnetic order (antiferromagnetism). However, the antiferromagnetic order limits its applications. This study demonstrates the induction of ferromagnetism in LaFeO3 by doping with cobalt, varying the level of cobalt from 0 to 0.5 mol. Moreover, the effects of cobalt on the crystal structure, magnetic and dielectric properties are described. The XRD results show that at doping concentrations lower than 0.3 mol, LaFeO3 maintains its orthorhombic structure (Pnma), while at higher cobalt concentrations the rhombohedral (R-3c) LaCoO3 phase emerges. In addition, cobalt doping induces ferromagnetism because cobalt occupies iron positions until the solubility limit is reached (0.3 mol). All samples present high relative permittivity values, which increase with increasing cobalt content and temperature. Furthermore, the presence of cobalt results in a decrease in the dielectric dissipation factor for cobalt contents lower than 0.3 mol, due to the inhibition in the formation of vacancies. However, the presence of LaCoO3 at high cobalt contents increases the dielectric losses due to the presence of a mixtures of phases. Moreover, the electric polarization curves exhibited weak ferroelectric behavior for ferrites with cobalt contents lower than 0.3 mol, and lossy improper ferroelectric type behavior for samples with higher contents.

Simultaneous treatment of trace pollutant and compound pollution using an effective n-ZnO@p-LaFeO3/3DOM SiO2 photocatalyst

To confront the complex challenges of removing trace and compound pollutants from wastewater, this research presents a novel photocatalyst, n-ZnO@p-LaFeO3/3DOM SiO2. Powered by visible light, this catalyst combines lanthanum ferrite and zinc oxide within a three-dimensional ordered macroporous silica framework. The 3DOM structure’s high surface area and porosity effectively concentrate pollutants, enhancing their interactions with reactive oxygen species (ROS) and notably reducing the ROS diffusion path. Impressively, it achieves over 96.5 % removal rates for both bisphenol A (BPA) and hexavalent chromium (Cr(VI)) at concentrations as low as 0.2 mg·L−1 within an hour. This study also discovers a synergistic effect in simultaneously oxidizing BPA and reducing Cr(VI). Moreover, it investigates the underlying mechanism, focusing on ROS generation and the crucial role of adsorption in the photocatalytic process. This study positions the presented photocatalyst as a promising solution to the intricate challenges of advanced oxidation processes (AOPs), showcasing an efficient strategy for comprehensive wastewater treatment.

Performance analysis of LaFeO3 perovskite solar cells: A theoretical and experimental study

Lanthanum ferrite (LaFeO3) is a potential candidate for Perovskite Solar Cell (PSC) application. The transition metal oxide has strong electron-electron correlation which results in an increase in quantum efficiency (QE) of PSC. In this investigation, we reported synthesis of LaFeO3 perovskite material, simulation of LaFeO3-based PSC followed by experimental validation. The sol-gel method was employed to prepare nanoparticles of LaFeO3 for PSC application. The prepared perovskite material is analyzed by XRD, SEM, EDS, UV–Vis and FTIR. The photovoltaic (PV) application of synthesized LaFeO3 material is studied by SCAPS-1D. The LaFeO3-based PSC is simulated with various ETLs such as TiO2, PCBM, IGZO, In2O3, C60, ZnO, SnO2, WS2 and HTLs of Cu2O, CuInSe2, Spiro-OMeTAD, P3HT, D-PBTTT-14, V2O5, CFTS, CBTS. The simulation outcomes of 64 distinct configurations deduced the eight-best performing PSCs. For these eight PSCs, impact of thickness of perovskite absorber layer, operating temperature, defect density, series and shunt resistance, work function of back contact, J-V characteristics and QE curve has been studied. We have achieved theoretical maximum efficiency of 13.03 % for the configuration of FTO/WS2/LaFeO3/CBTS/Au. The optimized structure has experimentally obtained maximum efficiency of 0.79 %. This shows that it is promising material for future PV application.

Envisioning the structural and room temperature impedance spectroscopy study of praseodymium modified lanthanum ferrites

Praseodymium-modified lanthanum ferrites with general formula La1-xPrxFeO3 [x = 0.0, 0.1, 0.3, 0.5] were prepared using the sol-gel auto combustion technique. The X-ray diffraction patterns of all samples supported the orthorhombic crystal structure with the Pbnm space group. With increasing Pr concentration, it was discovered that the average crystallite size dropped from 44.29 to 29.83 nm. An LCR metre was used to evaluate the frequency-dependent dielectric characteristics between 100 Hz and 1 MHz at room temperature. A single semicircle on the Nyquist plots highlights the impact of grain resistance on electrical behaviour. The depressed semicircles at intermediate frequencies might be created by the grain boundary effect, while semicircles depressed at high frequencies imply grain conduction. The dielectric behaviour of lanthanum ferrites is explained based on Koop’s theory. The loss factor resulting from domain wall resonance displayed the same dielectric constant dispersion behaviour. At high frequencies, orthoferrites were shown to have lower dielectric losses. This is due to the constrained motion of the domain wall, which suggests that magnetically tunable filters and oscillators are possible practical uses.

Influence of Bi3+ ions on structural, morphology, elemental, vibrational, optical, magnetic, NLO and optical limiting properties of lanthanum ferrites nanoparticles

Nanoparticles of LaFe1-xBixO3 were successfully synthesized through the microwave combustion process (MCP) employing l-alanine as the fuel source. XRD and FT-IR analyses conclusively confirmed the orthorhombic structure of lanthanum ferrite, with the mean crystallite size varying between 56.32 and 25.43 nm. The optical energy gap value, calculated from UV–vis spectra, fell within the range of 1.84 to 2.49 eV. EDX analyses verified the presence of Bi, La, Fe, and O elements. Furthermore, FE-SEM images exhibited the nanoparticles' distinctive aggregated spherical morphology. Notably, VSM analysis showcased the robust diamagnetic behavior of LaFe1-xBixO3 nanoparticles. In photoluminescence's spectra, the samples underwent excitation with a wavelength of 315 nm. The values of Hc (coercivity) and Mr (remanence) fell within the range of 121.98 to 332.39 Oe and 0.1592 to 0.0907 emu/g for LaFe1-xBixO3 respectively. Z-scan experiments yielded values for the nonlinear susceptibility, index of nonlinear refraction, and coefficient of nonlinear absorption. The findings from optical limiting studies serve as additional verification, underscoring the suitability of these materials as promising options for integration into devices, including optical switches and optical power limiters.

Sunlight assisted photocatalytic degradation of antibiotics by boron-doped lanthanum ferrite

In recent years, the development of multifunctional materials has gained significant attention due to their wide range of applications in various fields. Boron (B)-doped lanthanum ferrite (LaFeO3) has emerged as a promising multifunctional material due to its excellent electrical and photocatalytic properties. The present study reports the synthesis of boron (0.1 mol, 0.2 mol, or 0.3 mol) -doped LaFeO3 nanoparticles using the sol-gel method and their characterization using X-ray diffraction, FTIR, scanning electron microscopy, and UV–visible spectroscopy. The electrical conductivity and photocatalytic activity of the synthesized material were evaluated using the four-point probe technique and the degradation of antibiotics (ciprofloxacin). The results revealed that the B-doped LaFeO3 nanoparticles exhibited enhanced electrical conductivity. Comparing all the samples 0.3 boron doped LaFeO3 showed best photocatalytic activity (91.2 %) towards ciprofloxacin. Super oxide (O2−.) radical is the major oxidative species responsible for photocatalytic activity. However, doping of boron, which creates oxygen vacancies and increases the concentration of charge carriers, reduced the band gap energy enhances the light harvest ion leading to improved photocatalytic properties. The recyclability of the composite is checked for three consecutive cycles and proves its sustainability.

Cerium doped lanthanum ferrites obtained by sol-gel method: a magnetic and Mössbauer study

Cerium doped lanthanum ferrites obtained by sol-gel method: a magnetic and Mössbauer study

Electromagnetic interference shielding performance of lanthanum ferrite with MWCNT and graphene in the polyethylene polymer matrix in X-band frequency

In the present study, a combination of Lanthanum ferrite (LaFeO3) magnetic nanoparticles with multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP) was prepared and used as conducting filler. As prepared Nanofillers were incorporated with the Low-density polyethylene (LDPE) with the melt blending process. The polymer composite was used to study the electromagnetic interference (EMI) shielding behaviour from 8.2 to 12.4 GHz. The electromagnetic (EM) wave shielding was ascribed to the dielectric and magnetic loss phenomena by incorporating graphene, MWCNT, and LaFeO3. The maximum shielding effectiveness of 33.57 dB was obtained with the critical concentration of 50:5:40:5 wt% sample.

Synthesis, characterization, and performance assessment of a perovskite‐type nano photocatalyst for degradation of thiamethoxam

AbstractIt is essential to remove thiamethoxam (THMX) from surface water as it negatively impacts the ecology and neurological systems of insects. Hence, a study was conducted to degrade THMX with different compositions of LaFeO3/g‐C3N4 (LFCN) composites. Several methods, including X‐ray powder diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and field emission scanning electron microscopy (FESEM), were applied to characterize the synthesized photocatalyst. The influence of many parameters on degradation, for example, THMX concentration, dosage of catalyst, and pH were studied experimentally. The degradation was highest under both UV‐C and sunlight for the synthesized catalyst, 1% LaFeO3/g‐C3N4 (LFCN1), in comparison to graphitic carbon nitride (g‐CN), and bare lanthanum ferrite (LF). The degradation was around 95% for LFCN1 under UV‐C light having an intensity of 15 W/m2 whereas degradation was 71.8% with LFCN1 photocatalyst under sunlight at neutral pH in 120 min of reaction time. The increased activity of LFCN1 was attributable to an improved surface area and a lower band gap. The study of reaction kinetics indicated second‐order behaviour. Additionally, a probable mechanism for degradation was put forth.

Calcium oxide as synergistic catalyst for oxygen reduction reaction on strontium-doped lanthanum ferrite for SOFC

Calcium oxide as synergistic catalyst for oxygen reduction reaction on strontium-doped lanthanum ferrite for SOFC

Optical, magnetic, and electrochemical properties of a fluorite-perovskite Ce0.9Gd0.1O2-∂ - La0.6Sr0.4FeO3-∂ nanocomposite synthesized by one pot sol-gel auto-combustion route

Gadolinium-doped cerium oxide (Ce0.9Gd0.1O2-∂; CGO) and strontium-doped lanthanum ferrite (La0.6Sr0.4FeO3; LSF) are well-known compounds for their application in solid oxide fuel cells, dense oxygen permeable membrane, and high-temperature ceramic reactor. The superior electro-catalytic performance of these two individual oxides or their composites is well established as it originates from multivalent cations (Ce3+/4+ and Fe2+/3+/4+) and doping-induced defects like electrons, holes, and oxygen vacancies. This work focuses on synthesizing and characterizing composite taking CGO and LSF in different weight ratios, i.e., 10:90, 30:70, 50:50, 70:30, and 90:10 by sol-gel auto-combustion process. End members CGO and LSF were also synthesized for comparison purposes. All synthesized nanopowders (single phases and their composites) were characterized with X-ray diffraction (XRD) for phase identification and Scanning electron microscopy (SEM) for elemental composition analysis. XRD and SEM results established the formation of the required phase and targeted composition. The optical properties of the materials were evaluated with the help of ultraviolet–visible Diffuse Reflectance Spectroscopy (UV–Vis DRS). Tauc's approximation measured band gap energies, and all the composites showed a very high band gap in the 4.85–5 eV range. Magnetic properties such as saturation magnetization (Ms), remanence (Mr), and coercive force (Hc) were calculated from a magnetic hysteresis loop obtained from the Vibrating-sample magnetometer (VSM) experiment at room temperature. Furthermore, the law of approach to saturation (LAS) model was applied to more precisely calculate Ms and other essential parameters. In magnetic characterization, the LSF phase fraction controls the overall magnetic property of the composites. Electrochemical behavior, such as the composites' charge storage ability and stability were tested by cyclic voltammetry and chronopotentiometry method. All the samples exhibited good stability, and the highest specific capacitance of 26 F/gm was obtained for the composite sample (CL91) when only 10 % LSF phase was incorporated in the nanocomposite.

Design and preparation of novel LaFeO3/NiFe2O4 nanohybrid for highly efficient photodegradation of methylene blue dye under visible light illumination

Most dyes are carcinogenic; thus, they must be removed from the water to save aquatic and human life. Among the various methods, the photocatalytic degradation of dyes is attracting much attention due to the easy strategy driven by the solar light. Herein, we report the fabrication of nickel ferrite (NiFO), lanthanum ferrite (LFO) and their composite are utilized as a light-driven catalyst for the deprivation of significant commercial dyes. The straightforward microemulsion method is used to produce both pure ferrite materials and their composite counterparts. The phases of the synthesized materials were verified through XRD analysis while scanning electron microscopy was employed to examine their morphology. The average crystallite size of the LFO, NiFO and their composite was 53, 62 and 42 nm, respectively. The elemental composition of the pristine and composite was confirmed by the energy dispersive spectroscopic analysis, indicating no other impurity in the materials. The optical properties are analyzed via UV visible and photoluminescence to measure the band gap value of 2.05, 1.73 and 1.9 eV for LFO, NiFO and their composite, respectively. It is observed that the LaFeO3/NiFe2O4 has the highest photodegradation efficiency (92 %) as compared to the LFO (LaFeO3) and NiFO (NiFe2O4). The composite material also showed excellent reusability as well as good stability. It was also confirmed that OH radicals are the major contributor toward the dye degradation, as confirmed by the scavenger tests. The higher mineralization of methylene blue in the occurrence of composite as a catalyst may cause rapid charge transfers, as confirmed by EIS, and it may stop the recombination of electrons/hole pairs due to suitable band alignments.