One step hydrothermal synthesis of LaFeO3 perovskite

Abstract

This work describes the synthesis of LaFeO3 oxide, using a one-step hydrothermal synthesis route, to obtain a solid exhibiting superficial, morphological and textural properties useful for potential applications. The synthesis process starts from corresponding metal nitrates of lanthanum and iron in well-defined concentration and KOH as mineralizing agent. The reaction is developed in a Teflon-lined stainless steel autoclave at 300 °C for 14 days. The composition and surface area were determined with X-ray fluorescence (XRF) and nitrogen adsorption isotherms (BET), verifying the obtaining of a stoichiometric, high, and active phase of oxide. The crystalline structure was evaluated with X-ray diffraction analysis (XRD), showing a pure orthorhombic perovskite phase. TPR results show the development of three single steps at different temperatures, kinetically detectable and related with reduction of component oxides. Scanning and transmission electron microscopy (SEM-TEM) results showed a remarkable degree of crystallization, favouring a specific morphology as a result of the low consolidation temperature of the perovskite phase. Catalytic test by means of methane reaction, performed along 240 on stream, reveals a light deactivation rate, decreasing progressively 7.1% until 60% of methane conversion, indicating the improved morphological and surface characteristics for potential applications.