Preparation of sizes controlled supported metal catalysts and investigation of their thermal stability and catalytic performances

在这份工作中，我们有succeeded in preparing Pt-size？lled Pt/Al？D22？D2 O？D23？D2 catalysts by a novel preparation method using microemulOracle。当Pt复合纳米粒子在微填充中被使用时，在微填充中不同催化剂类型的Pt粒子的大小。The size of the Pt particles of the prepared Pt/Al-D22-D2O-D23-D2 catalysts could be？lled in range of 3.8-23.4 nm by changing the length of alkyl group in the complex-forming agents。The catalytic performances in NO-CO reaction over those Pt-size？lled catalysts thus prepared were investigated and compared with the catalytic performance of the Pt/Al-D22-D2O-D23-D2 catalysts prepared by the conventional impregnation method。It's found that the catalysts prepared using microemulsion exhibited a higher activity for NO reduction by CO than the one prepared by the impregnation method.The thermal stability of platinum particles of Pt/Aly D22 y D2O y D23 y D2 catalysts against sintering was examined heating the catalysts at 700℃ under air flow for 12 h。“催化剂的平台粒子是通过这种方法来准备的，因为这些粒子被部分嵌入在氧化铝中。”However，粒子的大小将成为更大的穿透力。这被认为是因为催化剂中的铂颗粒可以很容易地移动，因为它可以很容易地移动到铝支持的大孔隙大小。在不受粒子聚合的情况下，孔隙大小被压缩为催化剂。该催化剂是被压制前显示的极高热稳定性与催化剂相比较的。

In this work we have succeeded in preparing Pt-size controlled Pt/AlィイD22ィエD2OィイD23ィエD2 catalysts by a novel preparation method using microemulsion. When Pt-complex nanoparticles in microemulsion were used in the preparation, the Pt particle size of the catalyst varied with the precursor type in microemulsion. The size of the Pt particles of the prepared Pt/AlィイD22ィエD2OィイD23ィエD2 catalysts could be controlled in range of 3.8-23.4 nm by changing the length of alkyl group in the complex-forming agents.The catalytic performances in NO-CO reaction over those Pt-size controlled catalysts thus prepared were investigated and compared with the catalytic performance of the Pt/AlィイD22ィエD2OィイD23ィエD2 catalysts prepared by the conventional impregnation method. It was found that the catalysts prepared using microemulsion exhibited a higher activity for NO reduction by CO than the one prepared by the impregnation method.The thermal stability of platinum particles of Pt/AlィイD22ィエD2OィイD23ィエD2 catalysts against sintering was examined heating the catalysts at 700℃ under air flow for 12 h. The platinum particles of the catalysts prepared by this method were considered to be difficult to sinter, because the particles were partly embedded in the alumina. However, the particle size became larger due to sintering. It was considered that the platinum particles in the catalysts could move easily because of the large pore size of alumina support. In order to avoid aggregation of the particles, the pore size was decreased by pressing the catalysts. The catalyst thus pressed exhibited extremely high thermal stability compared with the catalysts before pressing.