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通过离子交换法制得Cu/SAPO-34菱沸石分子筛催化剂,同时研究了NH3和NOx(NO和NO2)在该催化剂上的吸附位、吸附强度、吸附量和吸附速率,得到了不同反应气氛在Cu/SAPO-34上的吸附性能及其在NH3选择性催化还原(NH3-SCR)反应中的作用.研究采用瞬态实验、程序升温脱附(TPD)和漫反射傅里叶变换红外光谱(DRIFTS)等方法进行表征实验.瞬态实验结果表明NH3是吸附性气体.程序升温脱附实验和红外漫反射实验结果表明NH3可以吸附在布朗斯特和路易斯酸性位上形成不同的NH3物种,它们显示不同的SCR活性.NH3在Cu2+上的吸附速率最快,且键强最强.NOx可以氧化并以硝酸盐/亚硝酸盐的形式吸附在Cu物种上.最后,本文讨论了NH3选择性催化还原反应过程中在Cu物种上的中间物种并推测反应机理.
The Cu / SAPO-34 chalcopyrite zeolite catalyst was prepared by ion exchange method. The adsorption sites, adsorption strengths, adsorption capacities and adsorption rates of NH3 and NOx (NO and NO2) on the catalyst were also studied. / SAPO-34 and its role in the NH3-SCR (NH3-SCR) reaction were investigated.Transient experiments, temperature programmed desorption (TPD) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS ), Etc. The transient results show that NH3 is an adsorptive gas.The results of temperature programmed desorption and infrared diffuse reflectance show that NH3 can adsorb on Bronsted and Lewis acidic sites to form different NH3 species, Different SCR activity.NH3 has the fastest adsorption rate on Cu2 + and the strongest bond.The NOx can be oxidized and adsorbed on the Cu species as nitrate / nitrite.Finally, NH3 selective catalytic reduction Intermediate species on Cu species during reaction and speculate on reaction mechanism.