Preparation of LaFeO₃ Perovskite Nanoparticles using the Nitrate Method (from Nitrate Precursors)

Introduction. Perovskite LaFeO₃ is a promising material due to its mixed ionic and electronic conductivity. The classic method for obtaining LaFeO₃ is the solid-phase reaction method, which includes several long cycles of ball milling and high-temperature sintering at 1400 °C. This paper presents the synthesis of LaFeO₃ nanoparticles using lanthanum and iron nitrates at 1200 °C, as well as the structural and photocatalytic properties of the obtained nanoparticles.

Materials and Methods. Perovskite LaFeO₃ nanoparticles were obtained by evaporating an aqueous solution of a mixture of La(NO₃)₃ and Fe(NO₃)₃, followed by annealing for 7 hours at 1200 °C. LaFeO₃ nanoparticles were studied by X-ray diffraction, SEM, EDX, UV-Vis diffuse light scattering, photoluminescence, and FTIR spectroscopy. The photocatalytic activity of LaFeO₃ nanoparticles was evaluated by the photocatalytic degradation of rhodamine B (RhB) solution; active radicals generated during photocatalytic reactions were determined by the "trapping" method.

Results. Nanoparticles of orthorhombic perovskite LaFeO₃ with an average crystallite size of approximately 63 nm were obtained; the band gap of LaFeO₃ nanoparticles was 3.21 eV. According to photoluminescence spectroscopy, LaFeO₃ nanoparticles exhibit low photoluminescence intensity, which indicates a low charge recombination rate. LaFeO₃ nanoparticles exhibit high photocatalytic activity in the UV range (350 nm). At a nanoparticle concentration of 40 mg per 50 ml of RhB solution (10 mg/l), the solution becomes discolored within 90 minutes; the active particles are OH-radicals.

Conclusion. It has been demonstrated that photocatalytically active LaFeO₃ nanoparticles with a size of t approximately 63 nm can be obtained using the nitrate method in one stage within 7 hours at a synthesis temperature of 1200°C. The LaFeO3 nanoparticles obtained using this method have high photocatalytic activity due to the generation of OH radicals upon irradiation with light of a wavelength of 350 nm.

The study was funded by the Russian Science Foundation (25-19-00458-P)