Mossbauer study of structural-chemical transformation in two-dimensional iron-oxygen nanostructures in the course of transport reduction

Structural-chemical transformations of quasi-two-dimensional iron-oxygen na nostructures occurring at transport reduction were studied using NGR spectr oscopy. It has been found that isolated iron-oxygen groups [i.e. groups con taining iron and oxygen atoms: =Si-O-Fe(OH)(2) and (=Si-O-)(2)-FeOH] formin g surface monolayers were not reduced at T = 400-600 degrees C because of t heir covalent bonding with the silica surface, Reduction of iron oxide micr oparticles (microstructures) at T greater than or equal to 600 degrees C re sulted in the formation of metal iron in the form of alpha-Fe. It has been revealed that in the course of transport reduction (TR) of the samples with deposited monolayers (one or four monolayers) at T greater than or equal t o 600 degrees C bulk phases of iron silicate and metal iron were formed. It has also been shown that the features of structural-chemical transformatio ns of supported iron-oxygen nanolayers were in relation with the specific c haracter of phase formation within nanoscale structures.