Effect of high lanthanum content and thermal treatment on mineralogical, textural, and structural properties of La-hydrotalcite-like compounds

Abstract

Hydrotalcites and their respective mixed oxides are widely employed as catalysts and catalytic precursors on several industry processes. A series of La-hydrotalcite-like compounds (LaHT) synthesized by direct co-precipitation with ultrasonic homogenization under low supersaturation conditions and their respective oxides were studied by powder X-ray diffraction (XRD), infrared spectrometry (FTIR), and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). The effect of thermal treatment (850 °C) and La3+ contents (55 ≤ La at.% ≤ 65) on the structure and texture of these minerals were investigated. Synthesis route was effective to produce LaHT as major mineral at all La samples. La carbonates and hydroxides were crystallized as accessory phases. At 850 °C, MgO-type oxides were crystallized as major phases.