Caracterização de MgFe e MgAl nanomateriais hidróxidos duplos lamelares

Abstract

Layered Double Hydroxides (LDHs) are composed of divalent and trivalent metallic cations arranged in lamellar structures. Between the metal layers, anions such as nitrates, sulfates, or carbonates are found. LDHs originate from brucite, or mineral clay, primarily made of Mg(OH)₂. The nanostructure of LDHs, the retention of various metallic cations in their layers, the hydroxyl (-OH) groups on their surface, among other aspects, suggest applications for LDHs in areas such as catalysts, catalyst supports, electrodes, adsorbents, and drug delivery. Understanding the physical and chemical properties of these materials is essential to optimize their application. To this end, this work aims to characterize two groups of LDHs, being one of the hydrotalcite type (MgAl) and another of the pyroaurite type (MgFe), both with different cation ratio. The characterization techniques used were Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS), and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Using Raman and FTIR, the functional groups and vibrational modes present in each sample were identified, and it was observed that the spectra exhibit bands with crystal lattice vibrations and interlayer species, indicating differences between the samples based on cation proportions. Structural morphology was obtained via SEM, and the elemental composition of the samples was determined using EDS and ICP-OES, with molar ratio values lower than expected.