European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK.
Department of Chemistry, University of Durham, Durham DH1 3LE, UK.
Nat Mater. 2016 Feb;15(2):178-82. doi: 10.1038/nmat4478. Epub 2015 Nov 16.
The chemical functionality within porous architectures dictates their performance as heterogeneous catalysts; however, synthetic routes to control the spatial distribution of individual functions within porous solids are limited. Here we report the fabrication of spatially orthogonal bifunctional porous catalysts, through the stepwise template removal and chemical functionalization of an interconnected silica framework. Selective removal of polystyrene nanosphere templates from a lyotropic liquid crystal-templated silica sol-gel matrix, followed by extraction of the liquid crystal template, affords a hierarchical macroporous-mesoporous architecture. Decoupling of the individual template extractions allows independent functionalization of macropore and mesopore networks on the basis of chemical and/or size specificity. Spatial compartmentalization of, and directed molecular transport between, chemical functionalities affords control over the reaction sequence in catalytic cascades; herein illustrated by the Pd/Pt-catalysed oxidation of cinnamyl alcohol to cinnamic acid. We anticipate that our methodology will prompt further design of multifunctional materials comprising spatially compartmentalized functions.
多孔结构中的化学功能决定了它们作为多相催化剂的性能；然而，控制多孔固体中各个功能空间分布的合成途径是有限的。在这里，我们通过分步去除模板和化学功能化相互连接的二氧化硅骨架，报告了空间正交双功能多孔催化剂的制备。通过从溶致液晶模板的二氧化硅溶胶-凝胶基质中选择性地去除聚苯乙烯纳米球模板，然后提取液晶模板，得到了分级的大孔-介孔结构。单独模板提取的解耦允许基于化学和/或尺寸特异性对大孔和介孔网络进行独立的功能化。化学功能之间的空间分隔和定向分子传输为催化级联中的反应顺序提供了控制；本文通过 Pd/Pt 催化肉桂醇氧化为肉桂酸来说明这一点。我们预计我们的方法将进一步推动包含空间分隔功能的多功能材料的设计。
