钠盐对V_2O_5-WO_3/TiO_2催化剂NH_3-SCR反应活性的影响

采用浸渍法制备了V_2O_5-WO_3/TiO_2催化剂,并通过浸渍不同浓度的Na_2SO_4和NaCl,研究了不同的钠盐种类及含量对催化剂NH_3-SCR反应活性的影响,以考察催化剂的抗碱性,并采用BET、XRD、XPS、FT-IR和NH_3-TPD等测试技术对催化剂进行了结构与性能表征.研究结果表明钠盐降低了催化剂的比表面积,导致催化剂表面V~(5+)=O和V-OH酸性位点数量以及表面化学吸附氧含量降低,从而降低了催化剂的反应活性.催化剂钠盐中毒后NO转化率显著降低,脱硝温度窗口变窄.

The Effect of Sodium Salts on Catalytic Activity of V2O5-WO3/TiO2 over NH3-SCR Reaction

The effect of different sodium salts on catalytic activity of V2O5-WO3/TiO2 over NH3-SCR reaction was investigated in order to observe its selective catalytic reduction and alkali resistance. Fresh V2O5-WO3/TiO2 catalysts containing different amounts of sodium compounds were prepared by means of impregnation method. The catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, X-ray photoelectron spectrometer, fourier transform infrared spectroscopy and temperature programmed desorption of ammonia. The results showed that the addition of sodium lowered specific surface areas, allowed the decrease of the number of V5+=O and V-OH acidic sites and resulted in a reduction of chemical adsorption oxygen on the surface, and therefore, leading to a lower catalytic activity and a narrower reaction temperature window.