Endo- and Exotemplating to Create High-Surface-Area Inorganic Materials

Porous and high‐surface‐area materials are of interest to many scientific communities. Templating pathways can be used to synthesize such materials with a high degree of control over their structural and textural properties. As templates molecular or supramolecular units are added to the synthesis mixture. They are occluded in the growing solid and leave a pore system after their removal. For such templates the term “endotemplate” is introduced. Alternatively, the templates can be materials with structural pores in which another solid is created, thus providing a scaffold for the synthesis. After removal of the scaffold, a porous or finely divided solid remains, depending on the connectivity of the template. Such a template is termed an “exotemplate”. By judicious choice of the templating procedure, unprecedented control of the structure and texture on length scales between nanometers and micrometers has been achieved over the last few years. Holey appropriate templates: Two different templating approaches for the creation of porous and high‐surface‐area solids are discussed. These methods are endotemplating, where template species are incorporated in the growing solid (see scheme, top), and exotemplating, where a rigid porous solid provides a scaffold for the formation of another solid (see scheme, bottom). Removal of both kinds of templates results in high‐surface‐area solids.