Promotional effect of antimony on the selective catalytic reduction NO with NH over V-Sb/Ti catalyst.

The effect of antimony on the selective catalytic reduction (SCR) performance and SO durability of V-Sb/Ti was investigated. The physicochemical characteristics of catalyst were characterized by various techniques, including Brunauer-Emmett-Teller (BET) surface area analysis, X-ray diffraction (XRD), NH/SO-temperature programmed desorption (TPD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs), X-ray photoelectron spectroscopy (XPS), and H-temperature programmed reduction (H-TPR). The V-Sb/Ti catalyst showed excellent activity in the range 200-300°C (compared with V/Ti), with an optimum achieved for 2 wt.% antimony. The total amount of acidic sites and NH adsorption characteristics did not affect the catalytic efficiency. The Sb fraction was highest for V-2.0Sb/Ti and exhibited a positive correlation with the V fraction. This phenomenon is related to the effect of synergistic between vanadium and antimony, promoting the conversion of V to V by Sb. Increasing the V fraction in V-Sb/Ti increased the catalytic activity, which was mainly attributed to enhanced catalyst re-oxidation capability due to the addition of antimony. Furthermore, the addition of antimony delayed the adsorption of SO onto the V-Sb/Ti catalyst surface, improving the resistance to this gas. Therefore, the addition of antimony to V/Ti improved NO conversion and SO durability.