Porous Inorganic Materials

Abstract

AbstractPorous inorganic materials cover a range of solids, both oxides and nonoxides, crystalline and amorphous, that have a pore size extending from about 3 Å to over 500 Å. Crystalline microporous materials such as zeolites have been known for over 200 years, and the research in the past decade has extended types of microporous materials from traditional oxides to chalcogenides and metal–organic frameworks. Efforts aimed toward developing new microporous materials that integrate uniform microporosity with other functionality have also led to promising results.Periodically ordered mesoporous materials are a recent addition to the family of ordered inorganic porous materials. They can be made in the presence of organized assemblies of organic molecules (e.g. amines, cationic, anionic, or nonionic surfactants) or polymers (e.g. amphiphilic block copolymers). Micellar solutions, lyotropic liquid crystals, and microemulsions can all serve as structure‐directing agents during the cocondensation of inorganic precursors with organic species. A number of synthetic pathways have been developed for the preparation of mesoporous solids in a variety of chemical compositions including silica, organosilica, transition metal oxides, chalcogenides, and even elemental forms such as carbon and platinum. Much progress has also been made in the control of macroscopic morphologies (e.g. films, fibers, monoliths, and spheres). The pore geometry is closely related to the nature of the organic assemblies and other synthetic parameters and can be controlled to a certain degree to allow the synthesis of mesoporous materials with the desirable architecture and properties.The past decade has also witnessed a rapid development in the synthesis of ordered macroporous materials and porous materials that are ordered at multiple‐length scales. Commonly used templates for the control of the macroscopic ordering include colloidal crystals such as latex or silica spheres and emulsion droplets. With the availability of a variety of inorganic porous materials, numerous applications are awaiting the exploration of materials researchers.