The study of deNOx catalyst in low temperature using nano-sized supports

Abstract

The present study pertains to a vanadium/titania-based catalyst for removing nitrogen oxides at a relatively low temperature window. More specially, the present study relates to a vanadium/titania-based catalyst containing VOx (x < 2.5) and having excellent ability to remove nitrogen oxides at a wide temperature window, particularly at a relatively low temperature window and a process for removing nitrogen oxides using the same. In this study, various TiO2 supports have been tested to determine the role of support. Raw TiO2 were examined a variety of physical properties. Also comparing with commercial V2O5/TiO2 catalyst, the activity of various VOx (x < 2.5)/TiO2 in this study have quite different values. To find the source of lattice oxygen in vanadium oxides, the effect of calcination conditions on the removal efficiency of nitrogen oxides was examined. When nitrogen instead of air was introduced as a balance gas in calcination step, the activity of catalysts in this study was not changed. That may indicate the source of lattice oxygen in vanadium oxides as that of TiO2. The results of X-ray photoelectron spectroscope (XPS) revealed that after vanadium oxides loaded the support, TiO2 was reduced to Ti2O3, etc. In the test of calcination temperature of a variety of vanadium/titania-based catalysts, it has been found that TiO2 supports affects the optimal calcination temperature, indicating that the difference of crystal structure, defect and binding energy in TiO2 may make inherent VOx (x < 2.5)/V2O5 molar ratios, respectively. Its ratio seems to be an index of activity.