Abstract
Nanosized V-Ce oxides supported on TiO2 (VCT) were prepared and utilized in the low-temperature selective catalytic reduction (SCR) of NO with NH3. Compared with the other V-Ce oxides-based catalysts supported on Al2O3, ZrO2, and ZSM-5, VCT showed the best SCR activity in a low-temperature range. The NOx conversion of 90% could be achieved at 220 °C. Characterizations including X-ray diffraction (XRD), scanning election micrograph (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption with NH3 (NH3-TPD), and temperature-programmed reduction with H2 (H2-TPR) showed that V1.05Ce1/TiO2 exhibited a good dispersion of V2O5, enrichment of surface Ce3+ and chemical-absorbed oxygen, and excellent redox capacity and acidity, which resulted in the best SCR performance at low temperature.
Highlights
Nitrogen oxides (NOx), as one of the main pollutants in the atmosphere, give rise to many environmental problems such as acid rain, photochemical pollution, and haze [1,2,3]
Researchers have been working on low vanadium catalysts in recent years, and excellent NOx conversion has been achieved on supported V2 O5 catalysts [12,13,14], but several problems still remain, especially for N2 selectivity
For the samples of V-Ce oxides supported on TiO2 (VCT), Al2 O3 (VCA), ZrO2 (VCZR) and ZSM-5 (VCZS), most of the strongest peaks in each X-ray diffraction (XRD) patterns belonged to their supports, respectively
Summary
Nitrogen oxides (NOx), as one of the main pollutants in the atmosphere, give rise to many environmental problems such as acid rain, photochemical pollution, and haze [1,2,3]. V2 O5 -WO3 /TiO2 and V2 O5 -MoO3 /TiO2 are the most widely used catalysts for NOx removal because of their high activity and N2 selectivity [7], but a series of problems still existed, such as the relatively narrow working temperature range of 300–420 ◦ C [8], the high oxidation ratio of SO2 to SO3 [5,9], the toxicity of vanadium species [10], and the formation of N2 O at relatively high temperatures [11]. In view of the defects above, much attention has been put into developing efficient SCR catalyst working in low-temperatures or wide range temperatures. Researchers have been working on low vanadium catalysts in recent years, and excellent NOx conversion has been achieved on supported V2 O5 catalysts [12,13,14], but several problems still remain, especially for N2 selectivity
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