Encapsulation of Supported Pt Nanoparticles with Mesoporous Silica for Increased Catalyst Stability

新合成策略被开发了在异构的催化剂包含支持的磅 nanoparticles 阻止他们的 sintering。模型催化剂被在 120-nm 硅石祷告上驱散 3-nm 磅 nanoparticles 首先准备。这些然后被 mesoporous 硅石的新鲜的层盖住，一些十纳米厚，并且蚀刻到重新暴露金属表面到反应混合物。 TEM 图象被用来证实每合成步的成功，并且为有氢的 cis-2-butenes 和 trans-2-butenes 的催化变换的公司滴定和运动大小被采用测试在蚀刻的处理以后获得的催化剂的复活的度，它不得不被调节给同时的最大的活动和最大的催化剂稳定性。结果包含了铂 nanoparticles 被显示象 1075 K 一样高在温度在锻烧期间抵抗 sintering，而没有防卫的催化剂被 875 K 看见到泉华。

A new synthetic strategy has been developed to encapsulate supported Pt nanoparticles in heterogeneous catalysts to prevent their sintering. Model catalysts were first prepared by dispersing -3-nm Pt nanoparticles on -120-nm silica beads. These were then covered with a fresh layer of mesoporous silica, a few tens of nanometers thick, and etched to re-expose the metal surface to the reaction mixtures. TEM images were used to confirm the success of each of the synthesis steps, and both CO titrations and kinetic measurements for the catalytic conversion of cis- and trans-2-butenes with hydrogen were employed to test the degree of re-activation of the catalyst obtained after the etching treatment, which had to be tuned to give simultaneous maximum activity and maximum catalyst stability. The resulting encapsulated platinum nanoparticles were shown to resist sintering during calcination at temperatures as high as 1075 K, whereas the unprotected catalysts were seen to sinter by 875 K.