Preparation, Characterization and Optical Property of LaFeO3 Nanoparticles via Sol-Gel Combustion Method

Mya Theingi,Kay Thi Tun,Nwe Nwe Aung

doi:10.28991/scimedj-2019-0103-5

Mya Theingi, Kay Thi Tun + Show 1 more

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https://doi.org/10.28991/scimedj-2019-0103-5

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Abstract

Perovskite LaFeO3 is one of the most useful materials for the application in a catalyst, gas sensors, and fuel cells, etc. LaFeO3 nanoparticles were synthesized by the citrate sol-gel method. According to the TG-DTA analysis on LaFeO3 xerogel powder, the proper crystallization temperature was found to be at 450 °C. The TEM images also show clear crystal formation was started at 450 °C. The LaFeO3 nanocrystalline particles were obtained by sintering the calcined powders at different temperatures (800 °C, 900 °C, and 1000 °C) for 4 hours. The resulting particles were characterized by XRD, EDXRF, FT IR, and SEM analysis. At 900 °C, the XRD pattern of LaFeO3 shows an orthorhombic crystal structure. The average crystallite sizes vary between 30-60 nm and the increase in crystallite size with increasing sintering temperatures and it may be due to the increase in grain growth. FT IR analysis shows strong La-O and Fe-O vibrations. Based on the XRD and FT IR data, the optimum sintering temperature was chosen at 900 °C. The SEM micrographs show that the morphology of LaFeO3 has small-sized grains with round shape. The optical properties were determined by UV-visible spectroscopy in the wavelength range of 300 nm-700 nm. The optical band gap energy values of LaFeO3 using Tauc’s plot were found to be about 2.45 eV. These results indicate that the LaFeO3 prepared by the sol-gel method has a relatively lower band gap value and so it can have the potential for photocatalytic applications.

Highlights

Perovskite-type oxides of general formula ABO3 (A = rare or alkali earth metals, B = transition metals) have become one of the most promising candidates due to their wide range of physical and technological properties, such as ferroelectricity, piezoelectricity, pyroelectricity, high-temperature superconductivity, magnetic behavior, and catalytic activity [1, 2]
We focus on the synthesis of LaFeO3 by sol-gel method followed
The small endothermic peak about 100 °C with 5.20 % weight loss has corresponded to the elimination of adsorbed water, the other endothermic peaks at ~ 231 °C with 30.55 % is corresponded to decomposition and the burn out of organic species in the powder, the peak at ~ 358 °C with 27.66 % corresponds to decomposition of remaining nitrate and the peak at ~ 544 °C with 17.30 % is corresponded to the formation of the expected perovskite phase of LaFeO3

Summary

Introduction

Perovskite-type oxides of general formula ABO3 (A = rare or alkali earth metals, B = transition metals) have become one of the most promising candidates due to their wide range of physical and technological properties, such as ferroelectricity, piezoelectricity, pyroelectricity, high-temperature superconductivity, magnetic behavior, and catalytic activity [1, 2]. These properties determine the use of such materials in many applications such as gas transducers, catalysts, solid electrolyte batteries and magnetic sensors [3, 4]. We focus on the synthesis of LaFeO3 by sol-gel method followed

Methods

Results

Conclusion