The mechanism of catalytic oxidation phosphine in liquid phase by transition metal magnetic catalyst in external magnetic field

Abstract

It was six transition metal magnetic catalysts (TMMC) of Fe3O4, La/Fe3O4, Cs/Fe3O4, Mn/Fe3O4, Ce/Fe3O4 and Pd/Fe3O4 that on the catalytic oxidation phosphine (PH3) were researched in external magnetic field (MF). It was found that transition metal (TM) and MF had significant effect on improving PH3 removal, where the Mn/Fe3O4 was the best TMMC for the catalytic oxidation PH3. When the Mn/Fe3O4:H2O was 1.5:5.0, reaction temperature was 50 °C, O2 content was 5% as well as the MF strength was 10.0 A, the PH3 purification efficiency could be up to 82.84% and last for 7 h. In addition, it was transmission electron microscope (TEM), Raman spectroscopy (RS) and comsol multiphysics (CM) that were applied to characterize and analyze the mechanism on liquid phase catalytic oxidation PH3, of which the MF strengthening effects were mainly divided into physical and chemical effects. The physical effects were that the particles were moved in the same direction by the MF, which made the catalysts contact with PH3 and O2 more homogeneous so as to improve the PH3 removal efficiency. While the chemical effect was that the chemical adsorption of PH3 and O2 was promoted by MF firstly on the surface of the particles under the action of Faraday force. Then the reaction of PH3 catalytic oxidation was promoted by TMMC. When the TMMC was magnetized by MF, the effect of Me2+/Fe3＋/Fe2＋ ions was further enhanced and finally the catalytic oxidation reaction of PH3 was further enhanced, which provided the direction for quickly harmless of PH3.