V2O5-CuO/TiO2催化剂中低温选择性催化NOx还原研究

浸渍法制备了一系列V₂O₅-CuO/TiO₂催化剂,考察中低温(200~300℃)条件下,以氨为还原剂选择性催化还原NO_x的活性,并利用比表面积及微孔孔隙分析仪(BET)、X射线衍射(XRD)对催化剂进行微观表征和分析。结果表明,500℃焙烧的2V16Cu/TiO₂催化剂展示了最佳的中低温催化活性和较宽的活性温度范围,在空速6.0×10⁴ h^-1、225℃条件下,NO_x转化率达97.3%,250℃时达到100%,温度升至300℃,催化活性仍保持在100%。XRD结果表明,随着Cu负载量的增加,逐渐显现CuO的特征峰。结合活性评价数据说明,CuO是VCu/TiO₂催化剂的主要活性组分之一,是降低SCR催化反应温度的重要因素。BET结果表明,CuO的负载对钒钛催化剂的表面结构有较大影响。耐硫性实验结果表明,添加钒氧化物制备的2V16Cu/TiO₂催化剂的抗硫性能有所改善。

Selective catalytic reduction of NOx on V2O5-CuO/TiO2 catalyst at middle-low temperature

In this paper,a series of TiO2 supported vanadium pentoxide and copper oxide catalysts were prepared by the impregnation method for selective catalytic reduction of NOx with NH3 at middle-low temperature(200~300 ℃).The catalysts were characterized by BET and X-ray diffraction(XRD).The results showed that 2V16Cu/TiO2 calcinated at 500 ℃ exhibited the best catalytic activity at middle-low temperature and quite wide temperature window.A 97.3% NOx conversion was obtained at 225 ℃ and a gross hourly space velocity(GHSV) of 6.0×104 h-1,and it reached 100% at 250~300 ℃.XRD results showed that the characteristic peak of CuO gradually emerged with the increase of CuO loading.CuO was the key active component of the VCu/TiO2 catalysts,and affected the catalytic activity at middle-low temperature significantly.The BET results showed that the CuO loading had great influence on surface structure of vanadium-titanium catalyst.The test of sulfur resistance performance showed that 2V16Cu/TiO2 which was prepared by the introduction of vanadium pentoxide improved its sulfur resistance performance slightly.