Characterization of FeOOH nanoparticles and amorphous silica matrix in a FeOOH-SiO2 nanocomposite

ENNAS, GUIDO;CASULA, MARIA FRANCESCA;Marras S;NAVARRA, GABRIELE;SCANO, ALESSANDRA;Marongiu G.

2008-01-01

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Abstract

A nanocomposite with an FeOOH/ SiO(2) ratio equal to 17.7wt% and the pertinent matrix, obtained by etching away the nanoparticles through reaction with hydrochloric acid, were investigated by XRD, TGA-DTA, heliostereopicnometry, BET, and TEM techniques. The study shows the presence in the nanocomposite of ferrihydrite nanoparticles phase with average dimensions around 4 nm. The FeOOH nanoparticles structure was analyzed by synchrotron X-ray diffraction data using the distribution difference curve method. The porous structure of the matrix resulting by etching away the nanoparticles differs significantly from that of a pure SiO2 sample obtained by hydrolysis of TEOS under the same operative conditions followed in the nanocomposite preparation.