制备条件对锰氧化物SCR脱硝性能的影响

Effects of preparation conditions on selective catalytic reduction of NO by NH_3 over MnO_x catalyst

分别考察不同沉淀剂、溶液pH、煅烧温度和煅烧时间对制备Mn Ox催化剂及其低温SCR脱除NO性能的影响,并借助XRD和BET等表征手段分析各催化剂的物相和孔隙特性。结果表明,不同沉淀剂制备的Mn Ox催化剂的低温活性依次为:Mn Ox(Na2CO3)>Mn Ox((NH4)2CO3)>Mn Ox(Na OH)>Mn Ox(NH4OH)。表征结果表明,Mn Ox(Na2CO3)和Mn Ox((NH4)2CO3)催化剂之所以表现出突出的低温SCR活性,归因于混合氧化态的无定型结构和较大的比表面积。优选Na2CO3沉淀剂制备Mn Ox催化剂,最佳的煅烧温度和时间分别为350℃和6 h,而溶液pH对制备的Mn Ox催化剂的催化还原NO活性影响不明显。

The effects of series precipitators,pH,calcination temperature and time on selective catalytic reduction of NO by NH3 over Mn Oxcatalyst were investigated,and the representative catalysts were characterized by X-ray diffraction（ XRD） and Brunauer-Emmett-Teller（ BET） analysis. The precipitators had significant influence on the catalytic performance at low temperature,and the catalytic activities were obtained as follows： Mn Ox（ Na2CO3） Mn Ox（（ NH4）2CO3） Mn Ox（ Na OH） Mn Ox（ NH4OH）. The results of XRD and BET analysis demonstrated that the prominent catalytic activities of Mn Ox（ Na2CO3） and Mn Ox（（ NH4）2CO3） catalysts were attributed to the amorphous structure and high surface area of Mn Oxcatalysts. The preferred calcination temperature and time for NO reduction on Mn Ox（ Na2CO3） catalyst were 350℃ and 6 h,respectively. The mixed solutions pH presented unconspicuous influences on the catalytic activity of Mn Ox（ Na2CO3） catalysts.