Department of Environmental Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; Department of Chemical Engineering, Columbia University, New York 10027, USA.
Department of Environmental Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China.
J Environ Sci (China). 2020 May;91:237-245. doi: 10.1016/j.jes.2020.01.010. Epub 2020 Jan 24.
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.
具有高催化活性和优异的抗 SO 和 HO 性能的 CuSO/TiO 催化剂被认为是用于 NH 选择性催化还原氮氧化物的有前途的催化剂。催化剂的性能在很大程度上受到煅烧温度的影响。在这里，深入研究了煅烧温度对 CuSO/TiO 催化剂的物理化学性质和催化活性的影响。首先制备了在不同温度下煅烧的催化剂样品，然后通过 N 吸附-解吸、X 射线衍射、热重分析、拉曼光谱、傅里叶变换红外光谱、X 射线光电子能谱、NH 程序升温脱附、H 程序升温还原和原位漫反射红外傅里叶变换光谱对催化剂的物理化学性质进行了表征。结果表明，较高的煅烧温度对催化剂有三个主要影响。首先，随着煅烧温度的升高，烧结和锐钛矿转化为金红石，导致比表面积减小。其次，在较高的煅烧温度下，CuSO 分解，导致 Brønsted 酸位（S-OH）消失，这对表面酸度有不利影响。第三，来自 CuSO 分解的 CuO 改变了催化剂的表面还原性，并有利于 NH 氧化为氮氧化物（NO）的过程。因此，在高温（≥600°C）下煅烧的催化剂的催化活性大大降低。
