Preparation of Crystalline LaFeO3 Nanoparticles at Low Calcination Temperature: Precursor and Synthesis Parameter Effects

Substantial effort has been devoted to fabricating nanocrystalline lanthanum ferrite (LaFeO3), and calcination is the crucial process of crystallization in both high-temperature strategies and wet chemical methods. Lowering the calcination temperature gives the ability to resist the growth and agglomeration of nanoparticles, therefore contributing to preserve their unique nanostructures and properties. In this work, we prepared crystalline LaFeO3 nanoparticles with a calcination process at 500 °C, lower than the calcination temperature required in most wet chemistry methods. Correspondingly, the experimental conditions, including stoichiometric ratios, pH values, precipitants, complexant regent, and the calcination temperatures, were investigated. We found that the crystalline LaFeO3 was formed with crystalline NaFeO2 after calcination at 500 °C. Furthermore, the structure of FeO6 octahedra that formed in coprecipitation was associated with the process of crystallization, which was predominantly determined by calcination temperature. Moreover, an illusion of pure-phase LaFeO3 was observed when investigated by X-ray diffraction spectroscopy, which involves amorphous sodium ferrite or potassium ferrite, respectively. These findings can help prepare nanostructured perovskite oxides at low calcination temperatures.

Sol-Gel Fabricated Transition Metal Cr3+, Co2+ Doped Lanthanum Ferric Oxide (LFO-LaFeO3) Thin Film Sensors for the Detection of Toxic, Flammable Gases: A Comparative Study

In this investigation we are reporting the rapid preparation of Perovskite LaFeO3 thin films prepared by sol-gel synthesis followed by spin coating method. The structural properties of the spin coated LaFeO3 thin films measured by X-ray Diffractometer which confirms the formation of monophasic, orthorhombic, Perovskite LaFeO3 material. The morphological features of the films were explore by the ease of scanning electron microscopy, where the crystalline LaFeO3 nanoparticles were observed. Energy dispersive spectroscopy was utilized for the determination of elemental composition. The electrical properties were carried out to confirm the typical semiconducting behaviour of LaFeO3 p- type semiconductor. The thin films were subjected for gas sensing study, the material was found to be very efficient gas sensors for LPG, petrol vapour, CO2, methanol, ethanol, acetone gases. The main object was to discuss comparative study, means, what changes in parameters may be observed due to doping elements. Here undoped LFO sensor showed excellent sensitivity to methanol vapours, while doped LFO sensors found to very sensitive for petrol vapours. The enhanced sensitivity by doped LFO may attributed to increase surface area due to dopants.While all parameter essential for effective sensor were investigated in detail like, response recovery, reusability, selectivity of both the sensors.

Superior Adsorption and Photocatalytic Degradation Capability of Mesoporous LaFeO3/g-C3N4 for Removal of Oxytetracycline

Mesoporous LaFeO3/g-C3N4 Z-scheme heterojunctions (LFC) were synthesized via the incorporation of LaFeO3 nanoparticles and porous g-C3N4 ultrathin nanosheets. The as prepared LFC were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, Raman spectra and N2 adsorption analysis. The structural analysis indicated that the reheating process and the addition of NH4Cl in the thermal polymerization were the key factors to get porous g-C3N4 ultrathin nanosheets and to obtain high specific surface areas of LFC. It remarkably enhanced the adsorption capacity and photocatalytic degradation of LFC for removal of oxytetracycline (OTC). The effect of the mass percentage of LaFeO3 in LFC, pH and temperature on the OTC adsorption was investigated. The LaFeO3/g-C3N4 heterojunction with 2 wt % LaFeO3 (2-LFC) exhibited highest saturated adsorption capacity (101.67 mg g−1) and largest photocatalytic degradation rate constant (1.35 L g−1 min−1), which was about 9 and 5 times higher than that of bulk g-C3N4 (CN), respectively. This work provided a facile method to prepare mesoporous LaFeO3/g-C3N4 heterojunctions with especially well adsorption and photocatalytic activities for OTC, which can facilitate its practical applications in pollution control.