La-doped ZnO Nanoparticles Research Articles

Unraveling the Complex Interactions: Machine Learning Approaches to Predict Bacterial Survival against ZnO and Lanthanum-Doped ZnO Nanoparticles.

The rise in antibiotic-resistant bacteria is a global health challenge. Due to their unique properties, metal oxide nanoparticles show promise in addressing this issue. However, optimizing these properties requires a deep understanding of complex interactions. This study incorporated data-driven machine learning to predict bacterial survival against lanthanum-doped ZnO nanoparticles. The effect of incorporation of lanthanum ions on ZnO was analyzed. Even with high lanthanum concentration, no significant variations in structural, morphological, and optical properties were observed. The antibacterial activity of La-doped ZnO nanoparticles against Gram-positive and Gram-negative bacteria was qualitatively and quantitatively evaluated. Nanoparticles induce 60%, 95%, and 55% bacterial death against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. Algorithms such as Multilayer Perceptron, K-Nearest Neighbors, Gradient Boosting, and Extremely Random Trees were used to predict the bacterial survival percentage. Extremely Random Trees performed the best among these models with 95.08% accuracy. A feature relevance analysis extracted the most significant attributes to predict the bacterial survival percentage. Lanthanum content and particle size were irrelevant, despite what can be assumed. This approach offers a promising avenue for developing effective and tailored strategies to reduce the time and cost of developing antimicrobial nanoparticles.

Structural, optical and magnetic properties of ZnO nanoparticles tailored by ‘La3+’ ions

For current research work, pristine and La-doped ZnO nanoparticles are synthesized by employing sol-gel technique. Concentration of dopant is varied (x = 0–0.1, ∆x = 0.02) in order to tailor structural, optical and magnetic properties of ZnO nanoparticles. Synthesized nanoparticles possess wurtzite hexagonal structure. Crystallite size is decreased with the increase in dopant concentration. Nano-grains appear in uniform and consistent shape after doping with ‘La’. Intrinsic defects such as oxygen vacancies and zinc interstitials become more prominent with the rise in ‘La3+’ content. Optical band gap of La-doped ZnO nanoparticles is decreased. The optical parameters such as extinction co-efficient, skin depth, refractive index, optical conductivity and dielectric constant are found to strongly depend on concentration of ‘La3+’ ions. Ferromagnetic behavior of ZnO nanoparticles is enhanced with the rise in dopant concentration. La-doped ZnO nanoparticles can be used for development of gas sensors, photocatalysts, optoelectronic and spintronic devices.

Photocatalytic and fluorescent chemical sensing applications of La-doped ZnO nanoparticles

Herein, we report the facile solution phase precipitation synthesis of ZnO nanoparticles doped with various concentrations, i.e. 1, 5 and 10 mol% of lanthanum (La). The synthesized nanoparticles were characterized in detail by several techniques which confirmed the high-density growth and well-crystalline nature of La-doped ZnO nanoparticles. The XRD results revealed the successful incorporation of 1 mol% La ions in the hexagonal wurtzite structure of ZnO; however, small XRD peaks of La2O3 were detected in 5 and 10 mol% La-doped samples. All the La-doped nanoparticles were found to be UV responsive. For the application prospective, all the synthesized nanoparticles were used as photocatalyst for the photocatalytic degradation of three toxic dyes, i.e. methyl orange (MO), Rhodamine B (Rh B) dyes and picric acid (PA). By detailed photocatalytic investigations, interestingly, 1 mol% La-doped ZnO was found to be most efficient photocatalyst towards the degradation of all three organic dyes. Further, the synthesized nanoparticles were also used as fluorescent probe for the fluorescence sensing of picric acid (PA). Remarkably, the 1 mol% nanoparticles exhibited highest sensitivity, i.e. lowest limit of detection (LOD) value (1.05 µM L−1) towards PA compared to 5 and 10 mol% (1.38 µM L−1) La-doped ZnO nanoparticles.

A facile one-pot flash combustion synthesis of La@ZnO nanoparticles and their characterizations for optoelectronic and photocatalysis applications

The successful one pot flash combustion synthesis of ZnO nanoparticles (NPs) with a diverse LA (La@ZnO) content was achieved simply and economically. X-ray diffraction confirms the synthesis of ZnO with a hexagonal crystal system. The vibrational bands are positioned at 100, 332, 380, 438 and 583 cm−1 for pure and La@ZnO NPs. FESEM images exhibit roughly spherical and oval morphologies of pure ZnO with particles size 120 nm and La@ZnO NPs with particle sizes in the 46–74 nm range. The particle size of a La doped ZnO sample increases with increase in concentration from 1.0 % to 7.5 wt.% of La. The evaluated energy gap of La doped ZnO NPs decreased from 3.220 to 3.210 eV as the concentration of La varied from 1.0–7.5 wt.% as estimated by Kubelka–Munk theory. The photocatalytic analysis of the as-synthesized ZnO nanoparticles is maximized at La (1.0 wt.%) and the mechanism of photocatalytic decolourization reaction is discussed. The results suggest that the La-doped ZnO nanoparticles can be used in optoelectronic and photocatalytic applications.

Antibacterial and heavy ion removal properties of La- and Ti-doped ZnO nanoparticles

In this study, antibacterial activity and the absorption of Cd(II) heavy metal ions by sol-gel synthesized pure, La-, and Ti-doped ZnO nanoparticles was studied. ZnO nanoparticles were characterized by XRD, SEM and EDS analysis. Also, synthesized nanoparticles were tested for their antibacterial activity against the clinical pathogens Klebsiella using disc well diffusion method. The absorption capacity of ZnO nanoparticles for eliminating Cd(II) from aqueous mediums was investigated at different concentration of dopants. A high absorption efficiency (93 mg g−1) of Cd(II) from its aqueous solutions at initial concentration of 300 mg L−1 by 8 at% of Ti-doped ZnO nanoparticles was achieved. The absorption capacity of ZnO increased from 32 mg g−1 for undoped ZnO to 62 mg g−1 for La-doped ZnO, and 94 mg g−1 for Ti-doped ZnO. The antibacterial examinations were performed under dark environment against extended spectrum β-lactamases (ESBLs) producing strains of Klebsiella pneumoniae demonstrated that the Ti-doped ZnO has a higher antibacterial activity than the pure and La-doped ZnO nanoparticles.

Preparation pure ZnO, La-doped ZnO nanoparticles using sol-gel technique: Characterization and Evaluation Antibacterial Activity

In this work, pure ZnO and La-doping ZnO nanoparticles were synthesized by using Sol-Gel technique followed by heat treatment calcinated at 450 °C for 3 h. The resulting samples were characterized by elemental analysis, like a XRD, FTIR and FESEM for structural and morphological properties and study the influence of different percentages of La to ZnO after heat treatment calcination as well as improving small size of crystalline size of doping ZnO especially at 0.50% and 0.75% of La. The effect of different percentages (0.25, 0.5 & 0.75%) of La doped ZnO were evaluated against gram negative (E. coli) which exhibits higher antibacterial activity than pure ZnO sample using plate count method.

Investigation on structural, morphology and photoluminescence properties of lanthanum doped zinc oxide nanostructure for optical application by co-precipitation method

The doping of semiconductor by rare earth metal nanoparticles is an effective way for increasing photo catalytic activity. The preparation of ZnO particles with different concentrations of La doping (0, 3, 5 and 7 at.%) via co-precipitation method, and the effects of lanthanum doping concentration on the structures, morphologies and photoluminescence properties were investigated by XRD, FESEM, EDAX and PL. The XRD results indicated that the synthesized La-doped ZnO nanoparticles had the pure wurtzite structure. The crystallite size calculated by Debye–Scherrer’s formula is in the range of 36–28 nm. In addition, increasing the doping concentration of La ions in ZnO increase the defects in ZnO lattice and hence resulting in UV emission, which indicate the presence of narrow band-gap in doped nanoparticles.

Enhanced Photocatalytic Degradation of Methylene Blue Dye, Opto-magnetic and Antibacterial Behaviour of Pure and La-doped ZnO Nanoparticles

The different doping concentrations of lanthanum (La)-doped ZnO nanoparticles were synthesized successfully using zinc acetate and lanthanum nitrate via wet chemical method. Characterization of the prepared sample was done by standard analytical techniques such as powder x-ray diffraction analysis (P-XRD), high-resolution scanning electron microscopy (HR-SEM), energy-dispersive spectroscopy (EDS), Fourier transformer-infrared (FT-IR) spectroscopy, photoluminescence (PL) and UV-Vis spectroscopy (UV-Vis), and magnetic studies (VSM). The structural analysis has been carried out by powder x-ray diffraction. X-ray diffraction studies revealed that the nanoparticles are well-crystalline and possess hexagonal wurtzite structure. HR-SEM images showed the homogenous spherical-shaped morphology of the synthesized ZnO nanoparticles. EDS analysis confirmed the presence of La ions into ZnO lattice. The band gap (Eg) energy was determined by UV-Visible spectral data, and it was found that the Eg value decreases with increasing the La concentration into ZnO lattice. PL spectra confirmed that the effective La doping enhance the UV and visible region near band gap emission. The effect of La doping on the photocatalytic activity of ZnO nanoparticles for the degradation of methylene blue dye was studied under solar illumination and the results showed that the La doping kindles appreciable degradation of MB. The optical density measurements of the ZnO nanoparticles against both gram-positive (Bacillus subtilis, Staphylococcus aureus) as well as gram-negative bacteria (Proteus mirabilis, Salmonella typhi) showed better bacterial activity than pure ZnO. Moreover, it showed that higher dopant La in ZnO exhibit efficient antibacterial activity.

Effective photocatalytic degradation of paracetamol using La-doped ZnO photocatalyst under visible light irradiation

Visible light-driven photocatalysts of lanthanum (La) doped ZnO nanoparticles were successfully prepared by a facile precipitation method using various La doping concentrations (0.5, 1.0 and 1.5wt%). La doping did not modify the crystallinity of ZnO significantly, but enhanced the optical absorption of visible light due to the reduction in particle size and band gap energy. La-doped ZnO photocatalysts were applied to treat 100mg/L paracetamol in aqueous solution under visible light irradiation after 3h. 1.0wt% La-doped ZnO photocatalyst showed the highest photocatalytic activity for the degradation of paracetamol with a degradation efficiency of 99% and TOC removal of 85%. Based on the chemical analysis of photocatalytic products detected, proposed mechanism for paracetamol removal by La-doped ZnO nanoparticles under visible light illumination including radical generation with use of photocatalytic degradation and subsequent reaction pathways was proposed.

Experimental investigation on the structural, dielectric, ferroelectric and piezoelectric properties of La doped ZnO nanoparticles and their application in dye-sensitized solar cells

Pure and lanthanum (La) doped ZnO nanorods were synthesized via co-precipitation method. The structure and morphology of as grown ZnO and La-ZnO nanoparticles were studied using transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) methods. The values of remnant polarization and coercive field were found to be 0.027μC/cm2 and 1.33kV/cm, respectively, for as grown La-ZnO nanostructures. High Curie temperature (276°C) for doped ZnO was observed in dielectric study. Piezoelectric coefficient at room temperature was found to be 101.30pm/V. I-V characteristics were studied for both pure and doped ZnO nanoparticles. Photo-anodes of dye-sensitized solar cells (DSSCs) were made using ZnO and La-ZnO nanorods. The conversion efficiency and short circuit current density of La-ZnO nanorods based DSSC were 0.36% and 1.31mA/cm2, respectively, which were found to be largely enhanced when compared with that of pure ZnO based DSSC (0.20% and 0.94mA/cm2).

Synthesis, characterization and photoluminescence property of La-doped ZnO nanoparticles

La-doped ZnO nanoparticles were synthesized via a facile and surfactant-free chemical precipitation route, and the effects of lanthanum doping concentration on the structures, morphologies and photoluminescence properties were investigated by XRD, TEM, EDX, PL and UV–Vis absorption spectra. The results showed that the La3+ ions were successfully incorporated into the ZnO host, and the products were well-crystalline. The average size and band gap of La-doped ZnO nanoparticles were varied with the lanthanum doping concentration. The average size of doped nanoparticles was much smaller as compared to that of undoped ZnO. The increasing of lanthanum doping concentration increased the defects in ZnO and resulted in a red shift of UV emission, indicating the narrow band gap in doped nanoparticles. This was probably attributed to the impurity energy levels in band gap introduced by substitutional La3+ ions.

Photocatalytic degradation of the Paracetamol drug using Lanthanum doped ZnO nanoparticles and their in-vitro cytotoxicity assay

The doping of semiconductor by rare earth metals nanoparticles is an effective way for increasing photocatalytic activity. Zinc oxide and Lanthanum doped Zinc oxide nanoparticles were synthesized by modifying the gel-combustion method. It was found that La can greatly enhance the cytotoxicity and photocatalytic activity of ZnO nanoparticles towards various cell lines and Paracetamol drug. These nanoparticles were characterized by various spectroscopic and other techniques which clearly revealed the presence of lanthanum ions. The absorption edge shifts towards the visible region after doping with La ions. This shift shows that the doping of La ions is favorable for absorbing the visible light. The comparative photocatalytic and cytotoxicity activity revealed that La doped ZnO nanoparticles remarkably enhanced activities as compared to the ZnO nanoparticles. The outcome of these studies offers valuable for planning La doped ZnO nanoparticles having cytotoxicity and photocatalytic activities helpful for the formulation of anticancer product and waste water remediation.

Photocatalytic degradation of Reactive Black 5 and Malachite Green with ZnO and lanthanum doped nanoparticles

Here we report the preparation of ZnO particles with different concentrations of La3+ doping (0, 0.5 and 1 wt%) via sol-gel method. The nanoparticles are synthesized directly from Zn(CH3COO)2.2H2O in the presence of 1-propanol and triethylamine at 80°C. The conditions are optimized to obtain particles of uniform size, easy to isolate and purify. The nanoparticles are characterized by SEM, XRD and UV-Vis analysis. The photocatalytic properties of pure and La-doped ZnO are studied in the photobleaching of Malachite Green (MG) and Reactive Black 5 (RB5) dyes in aqueous solutions upon UV illumination. It is observed that the rate constant increases with the La loading up to 1 wt%. The doping helps to achieve complete mineralization of MG within a short irradiation time. 1 wt% La-doped ZnO nanoparticles show highest photocatalytic activity. The La3+ doped ZnO particles degrade faster RB5 than MG. The reason is weaker N=N bond in comparison with the C-C bond between the central carbon atom and N,N-dimethylaminobenzyl in MG. The as-prepared ZnO particles can find practical application in photocatalytic purification of textile wastewaters.

Structural, morphological and luminescence studies on pristine and La doped zinc oxide (ZnO) nanoparticles

The pristine and lanthanum doped ZnO nanoparticles were synthesized by sol–gel method by the optimized conditions and parameters. The formation of ZnO nanoparticles was confirmed by powder X-ray diffraction, high resolution scanning electron microscopy, energy dispersive analysis and photoluminescence studies. The average size of pristine and La doped ZnO nanoparticles are decreased by increasing the concentration of La into the ZnO. At higher concentration of lanthanum, the particle size is increased. Photoluminescence properties of ZnO nanoparticles at room temperature were studied and the yellow–orange emission from the nanoparticles could be originated from the oxygen vacancy or interstitial based defects.

Room temperature ferromagnetism in Zn0.99La0.01O and pure ZnO nanoparticles

Room temperature ferromagnetism (RTFM) was observed in both La-doped and pure ZnO nanoparticles synthesized by the sol–gel method. RTFM is intrinsic according to the results of X-ray diffraction and X-ray photoelectron spectroscopy. The saturation magnetization (MS), the remnant magnetization at zero field and coercive field are 5 × 10−3, 7 × 10−4 emu g−1, 100 Oe for Zn0.99La0.01O nanoparticles and 1.5 × 10−4, 1 × 10−5 emu g−1, 50 Oe for pure ZnO nanoparticles, respectively. The magnetization is enhanced greatly by doping of La. Furthermore, the MS of Zn0.99La0.01O nanoparticles decreases from 0.005 to 0.001 emu g−1 as the annealing temperature increases from 500 to 700 °C. The doping of La introduces more oxygen vacancies into ZnO. The decrease of annealing temperature also produces more oxygen vacancies in La-doped ZnO. These results indicate that the origin of the RTFM is related to oxygen vacancies.

Novel infrared stealth property of cotton fabrics coated with nano ZnO: (Al, La) particles

Al, La doped ZnO nano particles were prepared through sol–gel method. The prepared ZnO: (Al, La) was coated on cotton fabric, forming a thin film to reduce infrared emissivity of the cotton fabric. Effects of Al contents on microstructure, infrared emissivity and infrared stealth of ZnO: (Al, La) coated fabrics were investigated by XRD, SEM, ICP, IR_2 dual-band emissivity measuring instrument and the infrared camera instrument. The addition of Al and La was favorable for providing more free electrons, improving scattering of infrared photon, and decreasing the infrared emissivity of ZnO: (Al, La) coated fabric in the range of 8–14 μm wavelengths. The hand covered by the coated fabric gave as low thermal radiation as the environment.

Synthesis, Characterization and Optical Properties of La-Doped ZnO Nanoparticles Prepared by Precipitation Method

ZnO and La-doped ZnO nanoparticles were synthesized by precipitation method by using Zn (CH3COO)22H2O, (CH2)6N4, (PEO)128-(PPO)54-(PEO)128 and LaCl3H2O as zinc source, precipitating agent, capping agent and dopant, respectively. The calcined samples exhibited a hexagonal wurtzite structure. The smallest particle size of pure ZnO nanoparticles of about 88 nm was obtained when 0.7 mmol (PEO)128-(PPO)54-(PEO)128 was used. The particle size of La-doped ZnO nanoparticles increased when La concentrations increased. The La-doped ZnO nanoparticles showed the energy band gap between 3.159-3.222 eV.

La-doped ZnO nanoparticles: Simple solution-combusting preparation and applications in the wastewater treatment

La-doped ZnO nanoparticles have been successfully synthesized by a simple solution combustion method via employing a mixture of ethanol and ethyleneglycol (v/v=60/40) as the solvent. Zinc acetate and oxygen gas in the atmosphere were used as zinc and oxygen sources, and La(NO3)3 as the doping reagent. The as-obtained product was characterized by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Experiments showed that La-doped ZnO nanoparticles exhibited the higher capacities for the removal of Pb2+ and Cu2+ ions in water resource than undoped ZnO nanoparticles.

Optical and photocatalytic properties of La-doped ZnO nanoparticles prepared via precipitation and mechanical milling method

The synthetic method used for preparing ZnO nanoparticles strongly influenced the products obtained. The ZnO powders incorporated more La when prepared by the mechanical milling method whereas the La2O3/ZnO composite nanoparticles were formed better using the precipitation method. The phase formations were detected by the X-ray diffraction technique and the morphology of the samples was followed by scanning electron microscopy. The La contents affected the crystallite size. This was explained by the formation of LaOZn on the surface of the samples and by the Zener pinning effect. The band gap energy of the samples was influenced by repulsion between the valence and conduction bands and the presence of a secondary phase. The photocatalytic degradation of a methylene blue solution by the samples depended upon the number of oxygen vacancies.

Structural characteristics and UV-light enhanced gas sensitivity of La-doped ZnO nanoparticles

La-doped ZnO nanoparticles were synthesized by sol–gel method starting from zinc acetate dihydrate, lanthanum sesquioxide, alcohol and nitric acid. The crystal structure and morphology of the nanoparticles were characterized by XRD, FESEM, respectively. The thermal decomposition behavior of the the ZnO-based xerogel was detected by TG-DSC. The results show that as-prepared nanoparticles with the hexagonal wurtzite contain the adsorbed water and some organic compounds below 300 °C, which is the key to the calcinations of the ZnO-based xerogel. Pure ZnO and La-doped ZnO thick film sensors were prepared and tested for specific sensitivity to alcohol and benzene with (and without) UV-light excitation. Among all, 10 at.%La–ZnO-based sensors are significantly sensitive to 100 ppm alcohol and 100 ppm benzene. There is an obvious enhancement of the gas-sensing performances with UV-light excitation. That is, the sensitivity to 100 ppm benzene rises twice. The observed sensitivity to alcohol and benzene could be explained with the surface adsorption theory and the conduction-band theory.