Anti-sulfur selective catalytic reduction of NOx on Sb-doped OMS-2

Abstract

Sb doped cryptomelane-type manganese oxides (Sb-OMS-2) with Sb/Mn molar ratios of 0–0.4 were synthesized and investigated for low-temperature selective catalytic reduction of NO by CO (CO-SCR). The resulting catalyst was characterized by X-ray diffractometer (XRD), specific surface area analyzer (BET), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). As a result, the doping of Sb increased the specific surface area and oxygen vacancy concentration of the catalyst. At the same time, most Sb entered the lattice of MnO6 to form Sb–O bonds, and a small number of Sb ions replaced K+ in the tunnel. Sb and Mn synergistically catalyzed the reduction of NO. Compared with undoped OMS-2, the NO conversion rate of Sb0.2-OMS-2 increased from 60% at 150 ℃ to 83%, and from 80% at 300 ℃ to 95%. In the presence of SO2, the NO conversion rate of Sb0.2-OMS-2 at 300 ℃ was 88%, while that of OMS-2 was only 60%.