碱土金属对MnOx-CeO2/ZrO2-PILC催化剂SCR活性影响研究

采用浸渍法模拟低温选择性催化还原(SCR)催化剂MnO_x-CeO₂/ZrO₂-PILC的碱土金属中毒特性,研究了碱土金属及其负载量对中毒程度的影响。实验表明,钙/镁的添加会引起催化剂中毒,催化剂中毒失活程度与碱土金属的负载量有关。运用 X射线衍射(XRD)、H₂程序升温还原( H₂-TPR)、氮气吸脱附及 NH₃程序升温脱附(NH₃-TPD)对新鲜催化剂以及碱土金属中毒后的催化剂进行了表征。结果表明,钙/镁中毒后催化剂的比表面积降低、催化剂氧化还原性和表面酸性减少,进而造成催化剂失活。

Effects of alkali metals on catalyst of MnOx-CeO2/ZrO2-PILC in the low-temperature selective catalytic reduction

The poisoning effects of alkali metals on low-temperature selective catalytic reduction (SCR) catalyst MnO_x-CeO₂/ZrO₂-PILC were invested by the method of impregnation in the laboratory. It was indicated that the addition of Ca/Mg would decrease the activities of the catalyst, and the poisoning effects were contacted with the amount and acidity of the doped-alkali metal. X-ray diffraction (XRD), H₂-temperature programmed reduction (H₂-TPR), N₂ adsorption-desorption and temperature-programmed desorption of NH₃ (NH₃-TPD) were used to characterize the properties of the fresh and alkali earth doped catalysts. According to the results, the doped-alkali metals would inhibit the reduction properties, induce the loss in surface area and surface acidity.