【摘要】 采用溶胶-凝胶法制备TiO₂-ZrO₂载体,以硝酸锰为前驱体采用柠檬酸溶液浸渍法制备Ce（n）-MnO_x/TiO₂-ZrO₂复合催化剂。通过XRD、SEM-EDS、XPS等测试方法对催化剂的物化性能进行表征分析,并进行NH₃选择性催化还原NO实验,考察其在低温下的活性及抗水抗硫性能。结果表明,Ce-Mn氧化物和TiO₂-ZrO₂载体间发生了相互作用,后者结晶度发生变化。与MnO_x/TiO₂-ZrO₂比较,Ce（n）-MnO_x/TiO₂-ZrO₂中Mn⁴⁺的含量提高。Ce元素以Ce⁴⁺、Ce³⁺存在于Ce（n）-MnO_x/TiO₂-ZrO₂中,在催化反应中能起到传递电子、离子和储氧的作用,提高催化剂的氧化还原能力,同时Ce元素的电离能和电负性要远小于Mn元素,优先于Mn发生化学反应,保护Mn元素的活性。Ce（0.2）-MnO_x/TiO₂-ZrO₂的颗粒分散均匀、粒径达到20nm左右。制备的Ce（n）-MnO_x/TiO₂-ZrO₂催化剂的低温活性和抗毒性都优于MnO_x/TiO₂-ZrO₂,其中Ce（0.2）-MnO_x/TiO₂-ZrO₂在80℃时脱硝效率为94%;100℃时脱硝效率达到100%,在同时通入5%H2O和100mg/m3 SO₂后,脱硝效率缓慢下降,反应210min降到85%后趋于稳定。更多还原

【Abstract】 Using the sol-gel prepared TiO₂-ZrO₂ carrier,Ce（n）-MnO_x/TiO₂-ZrO₂ composite catalysts were synthesized with critic acid solution impregnation method with manganese nitrate as MnO_xprecursor.The physical and chemical properties of catalysts were characterized with XRD,SEM-EDS and XPS.Meanwhile,its lowtemperature catalytic activities as well as sulfur and water resistance were evaluated with selective catalytic reduction（SCR）of NO by NH₃.The results show that there is an interaction between Ce-Mn oxide and TiO₂-ZrO₂ carrier,which leads to a crystallinity change in carrier.Comparing to the MnO_x/TiO₂-ZrO₂,there is a higher Mn⁴⁺ content in Ce（n）-MnO_x/TiO₂-ZrO₂.Furthermore,Ce in the Ce（n）-MnO_x/TiO₂-ZrO₂ exists as Ce⁴⁺,Ce³⁺state,which has the effect of transmission electron,ion and oxygen storage in the catalytic reaction,and then it improves the redox ability of catalysts.And ionization energy and electronegativity of Ce are much less than Mn.Therefore,Ce takes chemical reactions in preference to Mn.So the activity of Mn could be protected.The low temperature activity and antitoxic performance of Ce（n）-MnO_x/TiO₂-ZrO₂ are superior to MnO_x/TiO₂-ZrO₂.Among the prepared five catalysts with different molar ratios of Ce/Mn,Ce（0.2）-MnO_x/TiO₂-ZrO₂ demonstrates the best performance owing to the best particle dispersion and the small particle size about 20 nm,and a 94% denitrification efficiency can be achieved at 80℃and 100%at 100℃.When 5% H₂O and 100mg/m³ SO₂ are simultaneously added,the denitrification efficiency decreases slowly and stabilizes at85% after 210 min.更多还原