Effects of calcination temperature on physicochemical property and activity of CuSO/TiO ammonia-selective catalytic reduction catalysts.

CuSO/TiO catalysts with high catalytic activity and excellent resistant to SO and HO, were thought to be promising catalysts used in Selective catalytic reduction of nitrogen oxides by NH. The performance of catalysts is largely affected by calcination temperature. Here, effects of calcination temperature on physicochemical property and catalytic activity of CuSO/TiO 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 adsorption-desorption, X-ray diffraction, thermogravimetric analysis, Raman spectra, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of NH, temperature-programmed reduction of H 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 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 changed surface reducibility of the catalyst and favored the process of NH oxidation to nitrogen oxides (NO). Thus, catalytic activity of the catalyst calcined under high temperatures (≥600°C) decreased largely.