Highly Active Sb–V–CeO₂/TiO₂ Catalyst Under Low Sulfur for NH₃-SCR at Low Temperature

Abstract: The Cu based zeolite NH₃-SCR catalysts are well-known for after treatment of exhaust gases from light-and heavy-duty diesel engines. However, these catalysts are easily deactivated under the co-presence of H₂O and SO₂. In the present study, Sb–V–CeO₂/TiO₂catalyst showed superior conversion for the abatement of NO_xwith NH₃under H₂O and SO₂condition compared to commercial Cu–SAPO-34 and CuFe–ZSM-5 zeolite catalysts. The physico-chemical properties of fresh and used catalysts were examined by BET surface area, TEM (Transition electron microscopy) with EDS/EDX (Energy dispersive spectrometer/X-ray), XPS (X-ray photoelectron spectroscopy), DRIFTS (in situ diffuse reflectance infrared Fourier transformed spectroscopy) and H₂-TPR (temperature programmed reduction). Higher than 95% of initial NO_xconversion was obtained over Sb–V–CeO₂/TiO₂catalyst at 250 °C under 14% H₂O and 50 ppm SO₂conditions. The SO₂on/off test of the CuFe–ZSM-5 and Cu–SAPO-34 catalysts indicated a drastic decrease of NO_xconversion when SO₂was turned on. In contrast, Sb–V–CeO₂/TiO₂catalyst maintained a high NO_xconversion and initial NO_xconversion was completely recovered when SO₂was turned off. Graphical Abstract: [Figure not available: see fulltext.]