The Influence of Reduction Process on the Iron-Molybdenum Nanoparticles in Modified MCM-41 Silica

Abstract

Ironmolybdenum silica mesoporous materials were obtained by the application of direct hydrothermal method. The inuence of high temperature samples reduction in the H2 ow on their structural and magnetic properties was studied. Four samples with dierent metal contents relative to silica were investigated. The study was carried out by means of X-ray diraction, 57 Fe Mössbauer spectroscopy and the temperature programmed reduction method. With an increasing metals content, primary pores of MCM-41 transformed into the bottle-like pores, and then into the slit-like ones. Reduction and heat treatment caused the α-Fe, Fe2Mo, and FeMo alloy formation. Iron and molybdenum atoms after being released into the silica matrix, where they were embedded, create clusters or crystallites. It was observed that the high temperature reduction caused partial transformation of highly dispersed FeMo oxides species initially embedded in silica walls into crystallites big enough to give magnetic sextet component in the Mössbauer spectra.

The Current State of Application of Ultra- and Nanostructured Powders in Technologies in Welding Technologies (Review)

“…Ultra-and nano-structured powders have been already applied in different industries [7][8][9][10][11]. Diverse manufacturing procedures of nano-powders are available.…”