Pd/CeZrOx-Al2O3/Cordierite整体式催化剂的制备及其丙烷催化燃烧性能

Preparation of Pd/CeZrOx-Al2O3/Cordierite Monolithic Catalysts and Their Catalytic Performance for Catalytic Combustion of Propane

以堇青石蜂窝陶瓷为基体,以拟薄水铝石、稀土改性Al2O3和铈锆复合氧化物为涂层原料,用真空抽提法制备了CeZrOx-Al2O3/Cordierite载体,考察了pH、固含量和乳化时间等对涂覆效果的影响,然后用等体积浸渍法制备了Pd/CeZrOx-Al2O3/Cordierite整体式催化剂,考察了该整体式催化剂对于丙烷的催化燃烧活性。研究表明:当浆料pH为3.62、固含量(质量分数,余同)为38%、乳化时间为30 min时,浆料的涂覆效果最好(涂层上载量为127 g/L,涂层脱落率为0.2%);Pd/CeZrOx-Al2O3/Cordierite整体式催化剂(Pd负载量为2.0 g/L)对于丙烷的催化燃烧具有较好的活性(T50和T90分别为318℃和350℃),有较好的工业应用前景。

As volatile organic compounds(VOCs)are harmful to environment and human health,the purification of VOCs in the atmosphere has become more and more urgent.Among the various purification technologies for VOCs emission,catalytic combustion is considered to be the most effective one.Besides,cordierite ceramic carriers are widely used in industrial catalysis due to their high thermal stability and comparable hardness.Pseudo-boehmite,alumina modified by rare earths,and cerium-zirconium composite oxides were used as raw materials to prepare a slurry,in which alumina sol was acted as the binder.The optimum solid content of aluminum sol has been studied in previous studies.The emulsifier was used to obtain uniformly mixed slurry which was coated on a cordierite honeycomb ceramic carrier.CeZrOx-Al2O3/Cordierite scaffolds were prepared by vacuum extraction method.The effects of pH value,the solid content of slurry,and the emulsifying time on the coating performance were investigated.When pH value of slurry is 3.62,the solid mass fraction of slurry is 38%,and the emulsifying time is 30 min,the washcoat showed the best coating performance with a high loading capacity of 127 g/L and a low mass loss of 0.2%.Then Pd/CeZrOx-Al2O3/Cordierite monolithic catalysts were prepared by the incipient wetness impregnation method,and their catalytic performances for the catalytic combustion of propane were investigated.The catalysts were characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM).Pd/CeZrOx-Al2O3/Cordierite monolithic catalyst(Pd loading of 2.0 g/L)exhibited the best catalytic performance for the catalytic combustion of propane(T50 of 318°C and T90 of 350°C)among the studied catalysts,showing good industrial application prospects.