Preparation And Catalysis Of Supported Nano Iron-based Catalyst For Water-gas Shift Reaction

A kind of novel supported low-chromium and chromium-free iron-based catalysts for high temperature water-gas shift (WGS) reaction were prepared by absorbing nano maghemite on the supporters with large specific surface. The supported catalysts manifest high catalytic activity due to the high dispersion of Fe3O4 on the surface as discrete ultra fine particles and high concentration of crystal lattice bug on the surface.Supported WGS catalysts were characterized by XRD, TEM, DSC-TGA and XPS methods etc. The results show that chromium and transition metal oxides can enter the lattice of Fe3O4 acting as structural promoters, while the rare-earth metal oxides mainly act as electronic promoters due to their variable valence; Activated carbon supporter is inferior to MgAl2O4 spinel and oxidation treatment of activated carbon can improve the activity of carbon-supported catalysts. The molar ratio of ethylene glycol to ferric nitrate in the preparation of the maghemite colloid will affect the particle radius and absorption ability of colloid, then affect the catalytic activity.Supported catalyst samples FC/MA we prepared promoted by mini-chromium (0.7wt%) have almost the same activity as traditional Fe-Cr WGS catalysts; Chromium-free catalysts FN/MA-3 and FL/MA promoted by NiO and La2O3 respectively also have high activities, CO conversion of 95% (at 400) and 80% (at 350) were obtained. FN/MA-3 and FL/MA catalysts can be performed well under low steam/gas ratio and high space velocities conditions and have superior thermal stability and sulfur tolerance to the unsupported WGS catalysts.