SnO_2改性TiO_2对V_2O_5-WO_3/TiO_2催化剂结构和SCR性能影响

采用共沉淀法将SnO_2组分掺入到V_2O_5-WO_3/TiO_2催化剂载体TiO_2中,并通过多种物理化学手段,考察了不同SnO_2掺入量时对催化剂结构,表面分散物种和SCR性能影响.结果表明,SnO_2掺入到TiO_2中,元素Sn与Ti以Sn—O—Ti键形式相互作用,促进锐钛矿型TiO_2向金红石型TiO_2转变.在特定条件下,VO_x与WO_x物种和SnTi氧化物之间以V—O—Ti(Sn)和W—O—Ti(Sn)键形式相互作用,提高了VO_x物种可还原能力、促进了具有更多B酸酸量四面体WOx物种和V~(5+)物种生成.VW/SnTi催化剂表面VO_x物种与WO_x物种之间的相互作用更强.因此,VW/SnTi催化剂具有更好的SCR活性.

Effect of TiO2 Modulation by SnO2 on the Structure and SCR Performance of V2O5-WO3/TiO2 Catalysts

SnO2 additives were added to TiO2 carrier of V2O5-WO3/TiO2 catalyst by co-precipitation. The effect of SnO2 content on the structure, dispersed species and SCR performance of the catalyst was investigated by various physical and chemical methods. XRD, Raman and BET results showed that SnO2 additives can interact with TiO2 through Sn-O-Ti bond, promoting the TiO2 crystal transfer from Anatase to Rutile. H2-TPR, XPS and NH3-DRIFTS results showed that VOx species and WOx species can interact with SnTiOx oxide through V-O-Ti(Sn) and W-O-Ti(Sn) bonds. Under special circumstances, its could improve the VOx species reduction and favor the formation of V5 species and tetrahedral WOx species with more B acid site. Meanwhile, the interaction between VOx species and WOx species over VW/ST catalysts was enhanced. As a result, these advantages brought about the better catalytic activity for VW/ST catalysts.