堇青石蜂窝陶瓷载体酸处理对整体式La0.8Sr0.2MnO3催化剂催化甲苯燃烧性能的影响

整体式催化剂是一种常用的催化剂,蜂窝陶瓷载体是其重要组成部分。酸处理可以改进其结构上的不足。使用不同质量分数、种类的酸溶液对堇青石蜂窝陶瓷载体进行了预处理,考察了酸处理对整体式催化剂的基本性质及甲苯催化活性的影响,并采用XRD、BET等表征手段进行分析。结果表明,蜂窝陶瓷载体经质量分数为30%硝酸溶液处理后可达最佳效果,负载率提高48%以上,比表面积扩大20倍以上,由其制得的催化剂催化甲苯燃烧的起燃温度为219℃,降低了19℃,完全转化温度为281℃。表征结果说明酸洗过程未改变载体组成,而是使载体比表面积增加20倍以上,从而提高了整体催化剂的催化活性。

Catalytic Performance Toward Toluene Combustion of La0.8 Sr0.2 MnO3 Monolithic Catalyst with Acid-treated Honeycomb-shaped Cordierite Ceramic Support

Monolithic catalyst is a kind of frequently-used catalyst of which honeycomb-shaped ceramic support is an important part and its structure can be improved by acid treatment.We studied in this paper the catalytic per-formances toward toluene combustion of a series of La0.8 Sr0.2 MnO3 monolithic catalysts,in which the honeycomb-shaped cordierite ceramic supports were pretreated by acid solutions differed in concentration and acid type,by mea-surements of XRD,BET,etc..The different mass fraction and the kinds of acid are used to preprocess the cordierite honeycomb ceramics carrier.Results indicated that an optimized effect of the honeycomb-shaped ceramic support could be achieved while pretreated by 30wt% nitric acid solution,as the load rate increased by more than 48% and specific surface area was expanded by more than 20 times.The monolithic catalyst with that optimized pretreated support had a light-off temperature of 219 ℃ (declined by 19 ℃)and a complete conversion temperature of 281 ℃.The characte-rizations suggested an unchanged composition but a more than 20 times larger specific surface area,for the acid-treated support compared to untreated one,thus leading to promoted catalytic activity of the monolithic catalyst.