(x)WO3/TiO2-ZrO2 catalysts with different WO3 content were prepared by the impregnation method and the catalytic performance for the selective catalytic reduction of NOx with NH3 (NH3-SCR) was investigated in a fixed-bed stainless steel reactor. The catalysts were characterized by BET

XRD

NH3-TPD and in situ DRIFTS analysis of NH3 adsorption

and revealed the change of the structural property and acidic capacity. The characterization results showed that WO3 was in a well-dispersed state and WO3 addition enhanced the thermal stability of catalysts obviously. The adsorption and activation of NH3 were caused by TiO2-ZrO2 and WO3

respectively. It was found that W displayed a huge electronegativity and prompted the transfer of the N—H bond of NH3 from covalent bond to ionic bond

which could incur the NH3 activation. The results of catalytic activity indicated that the catalyst with 9%(mass) WO3 content exhibited 94% NO conversion within the wide temperature range of 320℃ to 420℃. (9%)WO3/TiO2-ZrO2 possessed comparatively higher intensity of Lewis acidity and larger amount of Brønsted acidity as well as more stable pore structure (4.4—1.7 nm). Besides

the absorption peak of the active intermediate species NH2 was more obvious. All these characters probably accounted for its better catalytic performance.