Doped Lanthanum Research Articles

Exploring the influence of lanthanum doping on pyroelectric and pyrocatalytic Characteristics in NBT-BT-2Zn ceramics

The present work investigates the pyroelectric properties of 0.94Na1/2Bi1/2TiO3-0.06BaTiO3-0.02Zn-xLa (NBT-6BT-2Zn-xLa; x = 0, 0.25, 0.5 and 1 in mole %) and its use in methylene blue (MB) dye degradation in wastewater. La doping is used to enhance the pyroelectric properties of NBT-6BT-2Zn for energy harvesting and pyrocatalysis applications. The 0.25 mol % La-doped sample consists of a maximum pyroelectric coefficient of 3.8 × 10−4 C m−2 °C−1 and shows a 55% MB dye decomposition. The presence of •OHandO2•− is confirmed by scavengers and radical trapping experiments. The repeatability test ensures the reusability of the NBT-6BT-2Zn-0.25La as a pyrocatalyst for dye degradation. The bulk form of NBT-6BT-2Zn-0.25La is also investigated to overcome the limitations of powder recovery in dye degradation.

Perovskite ceramics: the impact of lanthanum doping on the structural, radiation shielding and vibrational characteristics of lead titanate

Perovskite ceramics: the impact of lanthanum doping on the structural, radiation shielding and vibrational characteristics of lead titanate

Promoting effect of lanthanum doping on photovoltaic performance of CZTSSe solar cells.

A large open-circuit voltage (VOC) deficit is the major challenge hindering the efficiency improvement of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Cation substitution, or doping, is usually an effective strategy to achieve carrier regulation and improve efficiency. In this work, we developed a rare-earth element lanthanum (La) doped CZTSSe thin-film solar cell by directly introducing La3+ ions into the CZTS precursor solution. Such a proposed La doping approach could effectively enhance light harvesting, adjust the bandgap, and increase the electron diffusion length. Furthermore, appropriate concentrations of La doping can reduce harmful defect cluster. Benefiting from the La doping, the VOC significantly increases from 431 to 497 mV. Consequently, the power conversion efficiency is enhanced significantly from 6.54% (VOC = 431 mV, JSC = 25.50 mA/cm2, FF = 58.28%) for the reference cell to 10.21% (VOC = 497 mV, JSC = 35.20 mA/cm2, FF = 58.41%) for the optimized La-doped cell. This research provides a new direction for enhancing the performance of CZTSSe cells, offering promising prospects for the future of CZTSSe thin-film solar cells.

Experimental and ab initio studies of enhance photocatalytic efficiency of La-doped ZnO/g-C3N4 nanocomposites for bromothymol blue dye degradation

The ability of photocatalysis to clean up environmental contamination, notably in the treatment of water and air, has received extensive research. The composite materials synthesized by the coprecipitation method were made of ZnO and graphitic carbon nitride (g-C3N4) with various concentrations of lanthanum doping (La-ZnO). It was discovered that La metal ions were evenly distributed throughout the layered stacking structures of ZnO nanosheet, which had an impact on the band structure and increased the rate of electron-hole separation and visible light absorption. First-principles calculations show that La-doped ZnO-gC3N4 possesses a direct band gap and a type-II band structure with the conduction band minimum and the valence band maximum located in separate layers. A built-in electric field from the gC3N4 to the La-doped ZnO has been established through an analysis of charge density difference, Bader charge, work function, and band alignment. The electron-hole pair becomes spatially separated as a result, which increases the photodegradation activity. High interfacial charge transfer, efficient charge separation and migration, and high visible light optical absorbance were caused by the direct coating of ZnO on an ultra-thin g-C3N4 layer. The 0.6 % La-doped ZnO-gC3N4 degraded 97 % of the bromothymol blue (BB) dye, which was four times higher than the bulk ZnO, which could remove only about 21 % of the dye at the same time. The combined effects of lower photo corrosion, higher solar light usage owing to a hollow structure and heterostructured semiconductor photocatalysis contribute to this increased photocatalytic activity. The capacity of La-doped ZnO/g-C3N4 nanocomposite to effectively break down BB dye via photocatalysis suggests that it has the potential to address the problems associated with dye pollution in water systems.

Exploring the impact of multivalent substitution on high-temperature electrical conductivity in doped lanthanum chromite perovskites: An experimental and ab-initio study

Doped LaCrO3 perovskites hold promise as robust materials for electrical interconnects and sensor applications in harsh environments. In this work, we investigated the high-temperature behavior of La1–xSrxCrO3, La1–xCaxCrO3 and La0.8Sr0.2Cr1-x MnxO3 (0.1 ≤ x ≤ 0.4) through a combination of computational modeling and physical characterization up to 1500 °C. Crystalline structural properties were determined and compared with ab-initio calculations, which demonstrated excellent agreement with experimental findings. High-temperature electrical conductivity measurements were performed under different atmospheres. Calcium and strontium/manganese co-doped lanthanum chromites exhibited typical semiconductor exponential trends and conductivity showed proportional correlation with substitutions levels up to 30%. The DFT modelling was completed up to 1500 °C, including low and high temperature chromite phases and oxygen vacancies insertion. Calculations were correlated with experimental electrical properties. This work expands the understanding of doped lanthanum chromites and paves the way for the development of materials suitable for demanding high-temperature applications.

Acidification of La doped C3N4 for photocatalytic degradation of tetracycline

In this study, the photocatalytic performance of g-C3N4 is improved by doping lanthanum and hydrochloric acid acidification. The prepared samples were characterized by XRD, XPS, ICP, SEM, BET and UV vis DRS. From the SEM and BET results, it can be seen that both doping lanthanum and hydrochloric acid acidification can affect the microstructure of the sample to a certain extent, resulting in a larger specific surface area of the sample. According to UV–vis DRS, it can be determined that the doping of lanthanum and hydrochloric acid acidification have to some extent reduces the band gap of the sample, reduces the recombination rate of electron-hole pair in the sample, makes the photocatalytic process more likely to occur, and improves the photocatalytic performance. Compared with g-C3N4, g-C3N4/La samples have stronger photocatalytic performance, with a 2-hour photocatalytic degradation rate of 95.54 % for tetracycline in g-C3N4/La-400. Based on this, acidification of the sample can further improve its performance, and the 2-hour photocatalytic degradation rate of tetracycline in g-C3N4/La-HCl4 can reach 99.40 %. This study indicates that the doping of lanthanum and hydrochloric acid acidification treatment can improve the photocatalytic performance of g-C3N4. g-C3N4/La-HCl4 has certain application prospects in the degradation of tetracycline and other macromolecular organic compounds.

Synergistic Magnetocaloric Effect in Composite Materials Based on Mixed Doped Lanthanum Manganites

Synergistic Magnetocaloric Effect in Composite Materials Based on Mixed Doped Lanthanum Manganites

Catalyst Coatings for Ammonia Decomposition in Microchannels at High Temperature and Elevated Pressure for Use in Decentralized and Mobile Hydrogen Generation

We report an investigation of catalyst performance for the decomposition of ammonia under industrially relevant conditions (high temperatures of up to 800 °C and an elevated pressure of 5 bar) with further emphasis on their stability at high reaction temperatures. The catalysts were applied and tested as coatings in 500 µm wide channels of microreactors. Nickel-based catalysts were studied and compared to a ruthenium-based catalyst supported on SiO2. The effect of the support on the catalytic performance was investigated, and CeO2-supported nickel catalysts were found to exhibit the highest activity. Promoters were applied to increase the NH3 decomposition activity of the Ni/CeO2 catalysts. The addition of cesium led to a slight reduction in activity, while lanthanum, calcium, and barium doping resulted in increased activity. In particular, the barium-doped Ni/CeO2 catalyst showed very high ammonia conversion and closed the activity gap with respect to ruthenium catalysts at reactor temperatures of 650 °C and higher. The hydrogen production rates achieved in this work were compared to values in the literature and were shown to exceed values found earlier for both nickel- and ruthenium-based catalysts. Furthermore, the ruthenium-based catalysts under investigation were rapidly deactivated at 700 °C, while the nickel-based catalysts did not show deactivation after 220 h on time on stream at 700 °C.

Lanthanum-doped magnetic biochar activating persulfate in the degradation of florfenicol

In this study, lanthanum-doped magnetic biochar (LaMBC) was synthesized from bagasse by co-doping iron salt and lanthanum salt, and it was characterized for its application in the activation of persulfate (PS) in the degradation of Florfenicol (FLO). The results indicated that the LaMBC/PS system consistently achieved a degradation efficiency of over 99.5 %, with a reaction rate constant 4.71 times as that of MBC. The mechanism of FLO degradation suggested that O2•- and •OH played dominant roles, contributing 40.92 % and 36.96 %, respectively, during FLO degradation. Through physicochemical characterization and quenching experiments, it can be concluded that the key reasons for the enhancement of MBC activation performance are as follows: (1) Lanthanum doping in magnetized biochar increased the Fe(II) content in MBC. (2) Lanthanum doping significantly improved the adsorption capacity of LaMBC, increased the concentration of pollutants on the catalyst surface and effectively enhancing the reaction rate. (3) Lanthanum doping effectively increased the surface Fe(II) content during the reaction process in LaMBC, promoted the generation of active oxygen species in PS. This study delves into synthesizing and applying LaMBC for PS activation and FLO removal. The emphasis is on comprehensively characterizing and experimenting to elucidate the mechanism, proposing an innovative approach for efficiently degrading antibiotic wastewater.

Performance of PVDF-La dope TiO2 Membrane Photocatalytic Under Visible Light Irradiation for Produced Water Treatment

Membrane technology has been widely applied in water management systems for production, but is still hindered by fouling phenomena and low selectivity. Improving membrane performance through modification, such as the addition of photocatalytic materials, has been explored. In this research, La@TiO2 composite was incorporated into PVDF membranes for the treatment of produced water. Lanthanum doping on TiO2 effectively inhibits carrier recombination and enhances photocatalytic activity. According to the research results, adding the La@TiO2 composite to the membrane matrix increased the porosity value and membrane pore size. The PVDF-La@TiO2 1.5%wt membrane exhibited the highest flux values, specifically 20.59 L.m-2.h-1 and 40 L.m-2.h-1 in dark conditions and visible light irradiation. The rejection rates for COD, TDS, and ammonia were 69.89%, 57.77%, and 69.65%. The photocatalytic degradation effect of PVDF-La@TiO2 is proven by a significant difference in the filtration results under vis-light irradiation. The kinetics of COD removal are better described by a pseudo-first-order model. The degradation of PVDF-La@TiO2 1.5% pollutant demonstrated significant results, confirming its photocatalytic activity under irradiation. Overall, the membrane exhibited good performance and proved to be reusable after 6 hours of photofiltration. This research holds promise for enhancing the use of membrane photocatalytics in the treatment of produced water.

Effect of Lanthanum Loading on the Photocatalytic Degradation of Brilliant Yellow and Acid Blue Dyes in Visible Light and Sunlight over La2O3-TiO2 Nanocomposites

La-doped TiO2 nanocomposites were synthesized using the sol-gel process with different proportions of lanthanum doping (1-5 wt.%). The synthesized nanocomposites were analyzed thoroughly by X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) with extended X-ray diffraction (EDAX), transmission electron microscopy, ultraviolet-visible DRS spectra for optical properties, photoluminescence (PL) for emission behaviours, Fourier transform infrared (FTIR) spectroscopy (FTIR) for chemical bonding analysis and X-ray photoelectron spectroscopy (XPS) for surface chemical composition. The XRD analysis confirmed the anatase phase for all synthesized La-TiO2 nanocomposites. The UV-Vis spectra showed an increased absorption in the visible range and a slight red shift of binding energy as the % La doping increased from 1-5 wt.%. Similarly, the binding energy values varied from 3.02 to 2.75 eV with increased La doping. These nanocomposites exhibited the photocatalytic activity achieving 99% degradation of acid blue dye and 96% degradation of brilliant yellow dye in the presence of visible light irradiation. Scavenger studies indicated that the dye degradation was suppressed, suggesting the involvement of superoxide (O2–), hydroxyl radical (OH•) and holes (h+) in the reaction mechanism.

Comparison of Leakage Property with Varying Lanthanum Doping in (BiFeO3) 0.5-(baTiO3) 0.5

The new La doped BiFeO3-BaTiO3perovskite oriented material is synthesized through solid state reaction route technique at an optimized temperature 11000C. The structural investigation through XRD technique suggesting the phase of the materials are orthorhombic and tetragonal. The dielectric investigation through the shifting of tangent of loss and dielectric coefficient with frequency over a specific range of temperature gives indication of overall good dielectric feature of the material. Besides NTCR feature of the material is identifies through impedance spectroscopy. The leakage feature investigated through I-V characteristic technique suggesting good insulating property of the material for device fabrication and the effect of the property with increasing doping.

Impact of lanthanum doping on the electronic structure of oxygen vacancies in hafnium oxide

The electronic structure of oxygen vacancies in lanthanum-doped hafnium oxide (HfO2:La) is studied using the density functional theory. The simulation is carried out for the optimal structure of HfO2:La in three crystalline phases for an oxygen vacancy involved in the impurity charge compensation that is structural element, as well as for a second purposely added oxygen vacancy. It is shown that the HfO2 doping with La increases the oxygen vacancy content in such a way that the twice positively charged vacancy concentration increases and the neutral one decreases. The doping with La facilitates new oxygen vacancies formation in HfO2. Oxygen vacancies in HfO2:La and HfO2 have a similar electronic structure and are traps for electrons. However, the deeper trap and the electrostatic repulsion caused by the impurity in HfO2:La suppress the vacancies participation in the charge transport. Based on the obtained results, the mechanisms of HfO2-based resistive and ferroelectric memory improvements, when HfO2 doped with lanthanum, are discussed.

Lax-Zn3Al2-x-LDO electrocatalyst for effective tunable CO/H2 synthesis gas generation via CO2 reduction

During the electrocatalytic reduction of CO2 (CO2RR), the hydrogen evolution reaction (HER) emerges as an inevitable accompanying reaction. By utilizing the HER, regulating the product distribution of CO2RR can produce CO and H2 synthesis gas, which can convert to different value-added chemicals such as methanol and ethanol. So, La doping ZnAl-LDO catalyst (Lax-Zn3Al2-x-LDO, x = 0, 0.2, 0.4) was prepared by the urea method and was synthesized for CO2RR to CO/H2 synthesis gas. The catalysts are systematically characterized and analyzed by X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), and other multinomial characterization techniques to establish the relationship between different doping amounts and catalytic performance. Adding La can change the chemical environment of Zn2+/Al3+ ions and increase CO/H2 ratio range of synthesis gas, but excessive doping of La may result in a decrease in CO/H2 ratio. By precisely controlling the amount of lanthanum doping, meticulous regulation of the CO/H2 ratio in the synthesis gas can be achieved.

Optimized preparation of <i>c</i>-axis-aligned polycrystal of doped lanthanum silicate oxyapatite and evaluation of its electrical properties

Optimized preparation of <i>c</i>-axis-aligned polycrystal of doped lanthanum silicate oxyapatite and evaluation of its electrical properties

An efficient synthesis and characterization of La@MOF-808: A promising strategy for effective arsenic ion removal from water

Addressing serious waterborne arsenic issues, for the first time, lanthanum-doped MOF-808 (La@MOF-808) has been developed to remove total arsenic (Total As) and arsenite [As(III)] from water. This study involves the solvothermal synthesis of La@MOF-808, its characterization via FTIR, XRD, TGA, and SEM, in which distinct physicochemical attributes were identified, and the adsorption capacity of arsenic ions. The saturated adsorption capacity of La@MOF-808 for Total As and As(III) reached 282.9 mg g−1 and 283.5 mg g−1, as compared to 229.7 mg g−1 and 239.1 mg g−1 for pristine MOF-808, respectively. XRD and ATR-FTIR analyses underscored the central roles of electrostatic interactions and hydroxyl groups in the pollutant adsorption process. The impact of temperature, concentration, pH, and exposure duration times on adsorption performance was thoroughly investigated. The Langmuir model showed the maximum adsorption capacities (qmax) of La@MOF-808 was 307.7 mg g−1 for Total As and 325.7 mg g−1 for As(III), surpassing those of MOF-808 adsorbent, which suggests that monolayer adsorption occurred. Optimal adsorption was observed in a pH range of 2.0–7.0, and thermodynamic studies classified the process as spontaneous and endothermic. The adsorbent retains high capacity across repeated cycles, outperforming many standard adsorbents. Lanthanum doping markedly enhances MOF-808's arsenic removal, underscoring its potential for water treatment.

An investigation of the dielectric behavior of Bi0.7La0.3FeO3 compound under the influence of different calcination temperatures

This paper presents the synthesis and characterization of bismuth nanoferrite and lanthanum-doped bismuth nanoferrite (Bi0.7La0.3FeO3). The compounds were synthesized, through the sol-gel method and the doped compound was calcinated at three different temperatures 400 °C, 600 °C, and 800 °C. Following that, the compounds are further analyzed using several characterization methods such as; X-ray diffraction (XRD) analysis confirmed the formation of bismuth ferrite with a distorted perovskite structure and the R3c space group. The crystallite sizes were determined using Sherrer's formula, with bismuth nanoferrite having a size of 14.9 nm and lanthanum-doped bismuth nanoferrite calcinated at different temperatures exhibiting sizes of 13 nm, 17.7 nm, and 20 nm. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the presence of ferrite by observing metal-oxygen (M-O) stretching vibrations in the fingerprint region, with characteristic Fe-O bond peaks in the 430–480 cm−1 range. Ultraviolet-visible spectroscopy revealed promising energy band gaps for the synthesized compounds. Scanning electron microscopy (SEM) was utilized to examine the surface morphology of the compounds, revealing agglomerated structures. Dielectric properties of bismuth nanoferrite have been extensively studied, and lanthanum doping has been shown to improve them. The lanthanum-doped bismuth nanoferrite has a higher dielectric constant than bare bismuth nanoferrite. Additionally, there is less dielectric loss. Hence these results lead to significant potential for many applications, like gas sensors, memory devices, microwave devices, and biomedical applications.

Effect of Lanthanum Doping on Properties of ZnS Thin Films for Water Splitting

A chemical bath deposition technique was used to create the transparent, finely adherent ZnS and Lanthanum doped ZnS thin films on a glass substrate. The films were obtained in a water bath with reaction solutions containing Zinc, Lanthanum precursors, and trisodium citrate as a complexing agent. The amorphous nature of the films was confirmed by an X-ray diffractometer and the porosity of the films was checked by field emission scanning electron microscope. The presence of Lanthanum in ZnS films was confirmed by EDS. To find the band gap UV-Visible spectroscopy analysis was carried out. The impurity phase and the Raman modes were recognized by Raman spectroscopy. Further studies on the water splitting and photocatalytic degradation of organic dyes using La-ZnS nanomaterials are underway in our laboratory.

Lanthanum nitrogen Co-doped carbon quantum dots as optical and smartphone sensors for serotonin detection

A simple bottom up approach using hydrothermal technique was applied to prepare lanthanum and nitrogen Co-doped carbon quantum dots and were characterized by XRD, EDS, TEM, SEM FT-IR, XPS, fluorescence and UV-VIS spectroscopy to study their crystal structure, elemental and chemical composition, particle size, morphology and optical properties. It was found that morphology was spherical and particle size was 3–4 nm. EDS and XPS helps to prove the successful doping of lanthanum and nitrogen to carbon quantum dots with excitation and emission wavelengths 340 and 445 nm respectively. The intense blue color of fluorescent QDs were quenched with addition of serotonin due to the electrostatic interactions, π-π stacking interaction and may be due to complex formation between La,N-CQDs/Ser and the static quenching mechanism with inner filter effect has been observed. These La,N-CQDs were used as fluorescent probes for sensitive and selective detection of serotonin in a good linear range of 0–38 nM with low limit of detection 7.4 nM.The smartphone based portable detection was also developed for detection of serotonin providing the reliable information for analysis of color change and real sample analysis studies were also carried out. The uniqueness, high sensitivity and accuracy of the optical probe that was constructed are confirmed and this method's LOD is also highly competitive.

Engineering lanthanum into Pt doped CeO2 for Intermediate temperature solid oxide fuel cells

Platinum doped oxides with extremely low utilization of noble metal and excellent catalytic activity have gained attention in high-temperature electrochemical cells. However, platinum ions tend to be reduced in reducing atmospheres, resulting in the catalyst deactivation. In this work, lanthanum is introduced into Pt-CeO2, which aims to deal with the above problem and provides an approach to promote Pt-CeO2 based catalysts for intermediate temperature solid oxide fuel cells. In specific, lanthanum doped Pt-CeO2 catalysts are prepared and infiltrated into the anode. The results show the highest peak power density with 10 mol% lanthanum doped Pt-CeO2 among all samples. In-situ ambient pressure X-ray photoemission spectroscopy investigation reveals that the reducibility of CeO2 can be tailored by lanthanum dopants, which leads to exceptional stability of active Pt2+ in reducing atmospheres. Our results foster the development of more stable and inexpensive Pt-CeO2 for intermediate temperature solid oxide fuel cells.