整体式脱硝催化剂二氧化钛涂层制备

Preparation of titanium dioxide washcoat of monolith DeNOx catalysts

以硅溶胶为黏结剂,采用浆液浸涂法对堇青石蜂窝陶瓷基体进行涂覆,制备整体式脱硝催化剂的TiO2涂层。考察固含量、pH和不同添加剂等对TiO2浆液及涂层性质的影响,结合超声振荡、比表面积、扫描电镜和X射线衍射等手段对TiO2涂层进行表征。结果表明,随着固含量的增加,浆液黏度的增加速率逐渐加快,固含量超过22.82%时,浆液发生团聚,不可进行涂覆;随着pH的增大,浆液黏度先降低后增加,在pH为1.05时,浆液黏度最低;浆液中加入适量的聚乙烯醇、六次甲基四胺和铝溶胶均可提高涂层负载量,降低涂层脱落率。其中,在浆液中添加质量分数5%的铝溶胶可以使涂层负载质量分数增至8.58%,比表面积达10.22 m2·g-1,而涂层脱落率仅为12.84%,该涂层可作脱硝催化剂的良好载体。

Using silica sol as the binder,TiO2 washcoats on cordierite ceramic honeycomb were prepared by slurry coating.The effects of solid contents,slurry pH,and the additives on the properties of TiO2 slurry and coating were investigated.TiO2 washcoats were characterized by ultrasonic surging,BET,SEM and XRD.The results showed that the increasing rate of slurry viscosity enhanced gradually with the increase of solid contents,and when the solid content exceeded 22.82％,the slurry could not be used to coat because of its agglomeration;the slurry viscosity first decreased and then increased with the increase of pH,and the slurry viscosity was the lowest when the pH of slurry was 1.05 ; The coating content could be improved by adding appropriate polyvinyl alcohol,hexamethylene tetramine and alumina sol.The coating content of 8.58％ and surface area of 10.22 m2 · g-1 were obtained when 5％ alumina sol was added in the slurry.Moreover,the coating loss rate was only 12.84％,which could be used as the support of DeNOx catalysts.