WO_3(MoO_3)-V_2O_5/CeO_2-TiO_2/HM的制备及其脱硝性能

Preparation of WO_3(MoO_3)-V_2O_5/CeO_2-TiO_2/HM and its denitration performance

文章以HM沸石-TiO2为复合载体,负载以WO3或MoO3为助剂的V2O5涂层,制备了WO3(MoO3)-V2O5/CeO2-TiO2/HM作为NOx的SCR催化剂;采用XRD、N2吸附-脱附和NH3程序升温脱附(NH3-TPD)对催化剂结构、比表面积和酸性进行了表征;采用常压固定床微型反应器考察催化剂的脱硝性能,着重考察了V2O5质量分数对脱硝性能的影响。实验结果表明:HM沸石的加入有助于提高TiO2载体的比表面积,从而有利于V2O5以单分散态负载;V2O5负载量为8%的催化剂具有最佳脱硝性能,NO转化率达到93%;当V2O5负载量大于8%时,V2O5出现晶体相,催化剂活性反而下降。WO3(MoO3)对V2O5具有助催化作用,加入后使催化剂上有丰富的酸性位和适度的酸量,有利于催化反应的进行。

With WO3 or MoO3 as additive ,V2 O5 coatings was loaded to HM zeolite-TiO2 composite car-rier to prepare WO3 （MoO3 ）-V2O5/CeO2-TiO2/HM as NOx SCR catalyst .X-ray diffraction（XRD） , N2 adsorption-desorption and NH3 temperature programmed desorption （NH3-TPD） techniques were used to characterize the structure ,specific surface area and acidic nature of the catalyst .The denitra-tion performance of the catalyst was investigated by using the fixed-bed micro-reactor .The effect of V2 O5 content on the denitration performance was studied extensively .Experimental results showed that HM zeolite was beneficial to improving the specific surface area of the TiO 2 support and was help-ful to the dispersion of V2 O5 on the carrier in a monolayer state .The catalyst with 8% V2 O5 load dis-played the optimal denitration performance and the NO conversion rate reached 93% .When the V2 O5 load was larger than 8% ,V2O5 would be presented in crystalline phase on the catalyst ,which made the catalytic activity decrease .WO3 （MoO3 ） was helpful to the vanadium-based catalyst ,and made the catalyst possess abundant acid sites and proper acid content ,which was good for the catalytic reac-tion .