Inhibition Behavior for the Oxidation of Si-Doped Fe3O4: A Combined Ab Initio Molecular Dynamics and Experimental Study

Abstract

The magnetite oxidation process involves magnetite surface adsorption and O₂ dissociation, and the presence of impurity elements such as silicon inevitably affects the magnetite surface adsorption process. To explore and analyze the surface adsorption and oxidation behaviors of silicon-doped Fe₃O₄, thermogravimetric experiments and density functional theory methods are used to investigate the physicochemical properties of this material during magnetite oxidation. The results of experiments show that with the increase of SiO₂ content, the peaks of the oxidation reaction gradually migrate to the high-temperature region, the initial oxidation temperature of the mineral increases, and the average oxidation rate decreases. The results of calculations show that when the surface system is doped with Si atoms, the relaxation time of the adsorption and dissociation of oxygen on the surface is prolonged, and the presence of Si isomerization tends to stabilize the crystal lattice structure, reduce the migration of ions, and decrease the mineral's oxidizing properties.