Effects of calcination temperature on physicochemical property and activity of CuSO4/TiO2 ammonia-selective catalytic reduction catalysts

CuSO 4 /TiO 2 catalysts with high catalytic activity and excellent resistant to SO 2 and H 2 O, were thought to be promising catalysts used in Selective catalytic reduction of nitrogen oxides by NH 3 . The performance of catalysts is largely affected by calcination temperature. Here, effects of calcination temperature on physicochemical property and catalytic activity of CuSO 4 /TiO 2 catalysts were investigated in depth. Catalyst samples calcined at different temperatures were prepared first and then physicochemical properties of the catalyst were characterized by N 2 adsorption-desorption, X-ray diffraction, thermogravimetric analysis , Raman spectra , Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of NH 3 , temperature-programmed reduction of H 2 and in situ diffuse reflectance infrared Fourier transform spectroscopy . Results revealed that high calcination temperature had three main effects on the catalyst. First, sintering and anatase transform into rutile with increase of calcination temperature, causing a decrement of specific surface area. Second, decomposition of CuSO 4 under higher calcination temperature, resulting in disappears of Brønsted acid sites (S–OH), which had an adverse effect on surface acidity. Third, CuO from the decomposition of CuSO 4 changed surface reducibility of the catalyst and favored the process of NH 3 oxidation to nitrogen oxides (NO x ). Thus, catalytic activity of the catalyst calcined under high temperatures (≥600°C) decreased largely.