High and stable catalytic activity of Ag/Fe2O3 catalysts derived from MOFs for CO oxidation

Abstract

In this paper, highly active Ag/Fe2O3 catalysts derived from MIL-100(Fe) were synthesized by a traditional wet impregnation method. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), transmission electron microscopy (TEM), H2-temperature program reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The effects of Fe/Ag ratios and pretreatment atmosphere on the structure and catalytic activity for CO oxidation of Ag/Fe2O3 catalysts were investigated. It was found that rarefied oxygen environment in a muffle furnace was beneficial to the formation of small size Ag0 species and larger specific surface area, which could be due to the reductive gases (H2) produced by the decomposition of MIL-100(Fe) and nitrate. The Ag/Fe2O3 catalyst with Fe/Ag atomic ratio of 15 calcined in a muffle furnace showed a high catalytic performance (T100 = 160 °C), stability and reproducibility, which could be related to the large number of Ag0 species on the surface and larger specific surface area. In addition, the effect of water vapor on catalytic activity was also studied. The activity of Ag/Fe2O3 catalyst with Fe/Ag ratio of 15 was slightly affected by the 1 vol.% moisture in the feed gas, but still show high catalytic activity with T100 = 190 °C.