蜂窝陶瓷负载锰酸锶镧基催化剂制备及性能

采用不同浓度硝酸和草酸溶液,对堇青石蜂窝陶瓷载体进行预处理,考察了酸处理对载体失重率、吸水率及压缩强度的影响。采用催化剂粉体浆料涂覆法,制备了堇青石蜂窝陶瓷负载锰酸锶镧基La0.8Sr0.2Mn0.4Al0.4Zn0.2O3-δ(LSMAZ)整体式催化剂,运用X射线衍射(XRD)、扫描电镜(SEM)等手段对催化剂进行表征,并在管式反应器上进行甲烷催化燃烧活性测试。结果表明,酸处理能增大载体比表面积和吸水率;相同条件下草酸对载体的侵蚀效果优于硝酸;提高草酸浓度能增强侵蚀效果,但过高浓度的酸处理会使载体压缩强度过小而无法应用。经1050℃煅烧5 h后,所制备的整体式催化剂具有适宜的脱落率,无明显载体-LSAMZ界面反应,并具有最高的甲烷燃烧催化活性。

Preparation and catalytic activities of Lanthanum strontium manganite based catalysts supported on honeycomb ceramics

Cordierite Honeycomb ceramic supporters were treated by different concentrations of oxalic acid and nitric acid respectively.The effects of acid treatment on weightlessness rate,water absorption rate and compressive strength of the supporters were investigated.Cordier-ite Honeycomb ceramics supported Lanthanum strontium manganite based La0.8 Sr0.2 Mn0.4 Al0.4 Zn0.2 O3-δ（LSMAZ） catalysts were prepared by a catalyst powder slurry coating method.The resultant monolithic catalysts were characterized by X-ray powder diffraction （XRD）,field emission scanning electron microscopy （FE-SEM）.The catalytic performance for methane combustion was conducted in a tubular reactor. The results showed that acid treatment increased the specific surface area and water absorption of the supporters.Under the same condition, the erosive effect of oxalic acid on the supporters was better than that of nitric acid.The erosive effect was promoted with the increase of the oxalic acid concentration.However,the excessive concentration of acid weakened the compressive strength of the supporters,which were not used anymore.By calcining at 1050 ℃ for 5 hours,the resultant monolithic catalyst possessed moderate failure rate and insignificant inter-face reaction between support and LSMAZ,therefore,it also gave the highest catalytic activity for methane combustion.