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 °C for 24 h. The catalysts were characterized using N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction of H2 (H2-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 °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 H2-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 N2 and H2O could be the main reaction pathway, and oxygen adsorption might favor this process.

Graphical AbstractCuSO4 increased the activities of catalysts for the selective catalytic reduction of NO by NH3. A CuSO4/TiO2 catalyst had high tolerance of H2O and SO2.Figure optionsDownload as PowerPoint slide