Performances of CuSO4/TiO2 catalysts in selective catalytic reduction of NOx by NH3

A series of CuSO4/TiO2 catalysts were prepared using a wet impregnation method. The activity of each sample in the selective catalytic reduction of NO by NH3 (NH3-SCR) was determined. The effects of SO2 and H2O, and their combined effect, on the activity were examined at 340 degrees C for 24 h. The catalysts were characterized using N-2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction of H-2 (H-2-TPR), temperature -programmed desorption of NH3 (NH3-TPD), and in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS). The CuSO4/TiO2 catalysts had good activities, with low production of N2O above 340 degrees C. SO2 or a combination of SO2 and H2O had little effect on the activity, and H2O caused only a slight decrease in activity during the experimental period. The NH3-TPD and H-2-TPR results showed that CuSO4 increased the amounts of acid sites and adsorbed oxygen on the catalyst. In situ DRIFTS showed that the NH3-SCR reaction on the CuSO4/TiO2 catalysts followed an Eley-Rideal mechanism. The reaction of gaseous NO with NH3 adsorbed on Lewis acid sites to form N-2 and H2O could be the main reaction pathway, and oxygen adsorption might favor this process. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.