This study investigated the effect of Nb doping into V2O5-WO3/TiO2 (VWT) catalyst for removing NOxvia the SCR (selective catalytic reduction) by NH3. The experimental results exhibited that Nb can improve the reactivity of the VWT catalyst at low temperatures. The addition of Nb also enhanced the tolerance to SO2 and H2O. The de-NOx efficiency of the V2O5-WO3-Nb2O5/TiO2 (VWNbT) catalyst was increased up to 12% over that of the VWT catalyst at 240 °C when the catalyst was poisoned for 24 h. The prepared catalysts were characterized by FT-IR, XRD, XPS, and N2 physisorption, elemental analysis. The results showed that the ammonium bisulfate (ABS) was less formed in the VWNbT than in the VWT. Moreover, evolved gas analysis was performed to examine the thermal decomposition behavior of the poisoned catalyst, and confirmed that the ABS deposited on the catalyst was sufficiently decomposed between about 300 and 400 °C. In particular, to most effectively recover the characteristics and activity of the catalysts, thermal treatment at a temperature of 400 °C is suitable.
Keywords: Deactivation; Nb-doped V(2)O(5)–WO(3)/TiO(2); SCR (Selective catalytic reduction); Thermal regeneration.
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