Pr掺杂对V2 O5-MoO3/TiO2催化剂NH3-SCR反应活性的影响

摘要

V2 O5-MoO3/Pr6 O11-TiO2 catalysts were prepared by means of an impregnation method and TiO2 supports doped with different amounts of Pr were synthesized via a sol-gel method. The evaluation of selective catalytic reduction( SCR) activity indicated the catalysts with high activity and N2 selectivity in a temperature range of 220—400 ℃. And the Pr-doped catalyst also exhibited good resistance to SO2 and H2 O. The cata-lysts were characterized by means of X-ray diffraction( XRD) , N2 adsorption-desorption( BET) , X-ray photo-electron spectrometer( XPS ) and in situ diffuse reflectance infrared Fourier transform spectroscopy ( in situ DRIFTS) . The results showed that the specific surface areas of Pr-doped V2 O5-MoO3/TiO2 catalysts were lar-ger than that of the V2 O5-MoO3/TiO2 catalyst. Furthermore, the addition of Pr on V2 O5-MoO3/TiO2 catalyst could give more NH3 adsorption species, chemisorbed oxygen species, bridged nitrate species and the numbers of Brönsted acid sites, resulting in an enhance in the catalytic activity for NH3-SCR of NOx .%采用溶胶-凝胶法制备了不同Pr掺杂量的Pr6 O11-TiO2载体，并以浸渍法制备了V2 O5-MoO3/Pr6 O11-TiO2催化剂。活性评价结果表明，该催化剂在220~400℃范围内具有良好的脱硝效率和N2选择性以及较强的抗SO2和H2 O性能。表征结果表明，掺杂Pr可以提高V2 O5-MoO3/TiO2催化剂的比表面积、表面化学吸附氧物种浓度、桥式硝酸盐物种和 Brönsted 酸位数量，从而提高了催化剂上 NHx 的选择性催化还原( NH3-SCR)活性。