Controlled synthesis of perovskite LaFeO3 microsphere composed of nanoparticles via self-assembly process and their associated photocatalytic activity

The novel microspheres composed of perovskite LaFeO3 nanoparticles have been successfully prepared by hydrothermal method via self assembly process. Hydrothermal reaction conditions and citric acid concentration plays a vital role in the formation of LaFeO3 microspheres. The obtained microspheres have been structurally characterized by X-ray diffraction analysis (XRD) which confirms the single crystalline orthorhombic structure. The structural information was also confirmed from the Raman spectrum and the average crystallite size obtained from XRD increases with increasing hydrothermal reaction time. The composition and thermal decomposition processes of LaFeO3 were carefully investigated using energy dispersive spectroscopy (EDS) and thermogravimetric/differential thermal analysis (TG/DTA). Scanning electron microscopy (SEM) analysis indicates the formation of well-organized microspheres with an average diameter of 2–4 μm and transmission electron microscopy (TEM) images reveal LaFeO3 nanoparticles with an average size of 85 nm, which agrees well with the size obtained from XRD. A subsequent plausible formation mechanism of LaFeO3 microspheres has been explained in accordance with the Ostwald ripening process. The band gap energy was found to be 2.1 eV using UV–Vis diffuse reflectance spectrum. Furthermore, the photodegradation of Rhodamine B (RhB) in aqueous solution under visible-light illumination was evaluated.

► A simple citric acid-assisted hydrothermal method is developed to prepare novel LaFeO3 microsphere.
► This method presents a way to design and synthesis hierarchical architectures.
► The growth process of the microsphere composed of LaFeO3 nanoparticles can be controlled by hydrothermal condition and citric acid concentration.
► LaFeO3 microspheres exhibit good photocatalytic activity for Rhodamine B.