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The effect of synthesis methods on the activity of V/Ce/WTi catalysts was investigated for the selective catalytic reduction(SCR) of NO_x by NH_3. V/Ce/WTi-DP(deposition precipitation) catalyst showed excellent NH_3-SCR performance, especially the better medium-temperature activity and the less N_2O formation than V/Ce/WTi-IMP(impregnation). These catalysts were characterized by X-ray diffraction(XRD), Brumauer-Emmett-Teller(BET), X-ray photoelectron spectroscopy(XPS), temperature-programmed reduction(H_2-TPR), and in situ DRIFTS techniques. The XPS and H_2-TPR results revealed that V/Ce/WTi-DP exhibited more surface Ce species, higher level of Oα and higher reducibility of Ce species. Reflected by in situ DRIFTS results, the deposition precipitation method(DP) contributed to a greater amount of weakly adsorbed NO_2, monodentate nitrate and NH_3 species with better reactive activity. Meanwhile, the cis-N_2O_2~(2–) species, an intermediate for N_2O formation, was very limited. As a result, these advantages brought about the superior SCR activity and N_2 selectivity for V/Ce/WTi-DP.
The effect of synthesis methods on the activity of V / Ce / WTi catalysts was investigated for the selective catalytic reduction (SCR) of NO_x by NH_3. V / Ce / WTi-DP (deposition precipitation) catalyst showed excellent NH_3-SCR performance, especially the better medium-temperature activity and the less N 2 O formation than V / Ce / WTi-IMP (impregnation). These catalysts were characterized by X-ray diffraction (XRD), Brumauer-Emmett- Teller (BET), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (H_2-TPR), and in situ DRIFTS techniques. The XPS and H_2-TPR results revealed that V / Ce / WTi-DP exhibited more surface Ce species, higher level of Oα and higher reducibility of Ce species. Reflected by in situ DRIFTS results, the deposition precipitation method (DP) contributed to a greater amount of weakly adsorbed NO 2, monodentate nitrate and NH 3 species with better reactivity activity. Meanwhile, the cis-N 2 O 2- species, an intermediate for N_2O formation, was very limited. As ar esult, these advantages brought about the superior SCR activity and N 2 selectivity for V / Ce / WTi-DP.