Influence of silicon on local structure and morphology of γ-FeOOH and α-FeOOH particles

The extended X-ray absorption fine structure (EXAFS) method was used for investigating the local structures of lepidocrocite and goethite with and without silicon. The structure and morphology of these particles were investigated using X-ray diffraction and transmission electron microscopy, respectively. The bonding structure was examined by Fourier transform infrared spectroscopy (FT-IR). When silicon species was added, the structure and morphology changed while the linkage of FeO₆ octahedral units was distorted. The FT-IR spectra revealed the formation of the Fe-O-Si bond in particles containing silicate ions, and the characteristic bond affects the local structure and morphology of the particles.