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用溶胶凝胶法制备了Mn-Ce/TiO2(用M表示)和Cu-Ce/TiO2(用C表示)催化剂,将M相、C相和V2O5-WO3(用V表示)用顺序浸渍法依次负载到堇青石蜂窝陶瓷载体(CC)上。用尿素选择性催化还原NOx(SCR)的转化率作为衡量指标对一系列的整体催化剂性能进行评价。催化剂的物理化学性能用N2吸附、CO2-TPD、NH3-TPD、XRD、XPS和H2-TPR等进行表征。结果表明,当M相优先于C相负载到CC上时,在0.01%SO2和10%H2O存在的情况下,V/3C/3M/CC复合催化剂仍比C相或M相单独负载到堇青石上表现出较高的活性,并且微量的SO2有利于催化剂活性的提升。XRD分析结果表明,Cu-Ce负载到TiO2溶胶上有助于锐钛矿相的形成,Mn-Ce负载到TiO2上有助于金红石相的形成。比表面积只与M或C相的负载量有关而与负载顺序无关。M或C相能够增加催化剂表面不同强度的酸性位。H2-TPR研究结果表明,V和Cu或Mn之间的相互作用提高了V的还原能力,进而增加了耗氢量。由XPS分析可知,催化剂表面较高的V4+/V5+比值和大量化学吸附氧的存在有利于催化剂活性的提升。
Mn-Ce / TiO2 (indicated by M) and Cu-Ce / TiO2 (indicated by C) catalysts were prepared by the sol-gel method. The M phase, C phase and V2O5-WO3 Load onto Cordierite Honeycomb Ceramic Carrier (CC). The conversion of urea-selective catalytic reduction of NOx (SCR) was used as a measure to evaluate a range of overall catalyst performance. The physicochemical properties of the catalysts were characterized by N2 adsorption, CO2-TPD, NH3-TPD, XRD, XPS and H2-TPR. The results show that the V / 3C / 3M / CC composite catalyst is still supported on cordierite alone than C phase or M phase in the presence of 0.01% SO2 and 10% H2O when M phase is loaded onto CC preferentially than phase C, Showed a higher activity, and trace SO2 is conducive to the promotion of catalyst activity. The results of XRD analysis show that the Cu-Ce supported TiO2 sol contributes to the formation of anatase phase and the Mn-Ce loading on TiO2 contributes to the formation of rutile phase. The specific surface area is only related to the load of M or C phase regardless of the load sequence. M or C phase can increase the strength of the catalyst surface of different acidic sites. H2-TPR results show that the interaction between V and Cu or Mn increases the reducing ability of V, which in turn increases the amount of hydrogen consumed. According to XPS analysis, the higher V4 + / V5 + ratio of the catalyst surface and the presence of a large amount of chemisorbed oxygen are favorable for the improvement of the catalyst activity.