Nanoparticle Approaches to Zeolitic Catalysts

沸石（多孔铝硅酸盐）是一些最重要的工业催化剂。全世界都认识到操纵沸石以提高功能的重要性。《科学》杂志（2011,334,1629）将这一领域评为十大最重要的研究之一。这一提议似乎完全改变了我们对沸石催化剂制备的看法。这将通过一种全新的方法来实现，即采用一种已知的具有特定结构和化学性质的沸石，并有选择地将固体分解成精确定义的纳米颗粒，然后将其重新组装成新的材料。关键的概念是沸石中的某些取代基（尤其是Ge）自然地位于结构的特定区域，与Al/Si相比，它们在水解方面也不稳定。这意味着我们可以把锗放到沸石的特定位置，然后再把它溶解出来，把沸石分解成纳米结构的颗粒。重组的关键是纳米颗粒来源于完全凝聚的沸石，这意味着它们在几何上与重组兼容——这对于直接合成的纳米颗粒来说是不成立的。这是一种制造沸石的变革性方法，因为它提供了一种全新的机制，将产生新的结构，并将改变人们对如何制造沸石的看法。拆解的化学性质意味着一个人无法重新组装成原来的结构——你肯定会得到一个不同的结构。我们还建议这些结构应该是可预测的——设计用于应用的沸石的目标是该领域的圣杯之一。

Zeolites (porous aluminosilicates) are some of the most important industrial catalysts. There is worldwide recognition of the importance of manipulating zeolites to give improved functionality. The journal Science (2011, 334, 1629) rated this area of current research as one of the 10 most important. This proposal looks to completely change the way we think about the preparation of zeolite catalysts. This will be done through a completely new approach of taking a known zeolite of specific structure and chemistry, and selectively diassembling the solid into precisely defined nanoparticles which can then be reassembled into new materials. The key concept is that certain substituents in zeolites (particularly Ge) are naturally located in specific areas of the structure and are also hydrolytically unstable compared to Al/Si. This means that we can put Ge into only certain places in a zeolite, and then dissolve it out again to diassemble the zeolite into nanostructured particles. The key to the reassembly is that the nanoparticles have originated from a fully condensed zeolite, which means they are geometrically compatible with reassembly - this is not true for directly synthesised nanoparticles. This is a transformative approach to making zeolites because it offers an entirely new mechanism, will produce novel structures and will change the thinking in how zeolites can be made. The chemistry of the disassembly means that one cannot reassemble into the original structure - you will be guaranteed a different one. We also propose that these structures should be predictable - the goal of a designer zeolite for applications is one of the holy grails of the field.