Porous Inorganic Materials

Abstract

Porous 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.

Efficient reinforcement of wet gel by embedded polymer as newly approach for silica aerogel

“…Regarding to IUPAC standard, adsorption isotherms of all samples are attributed to type‐IV, indicating existence of structure of mesoporous in the aerogels 41 . The type‐IV isotherm indicates a fast increase at high relative pressure and appearance a hysteresis loop in many cases, which is associated with capillary condensation in mesopores 42 . The appeared hysteresis loop in SA1 sample reveals the type H‐1, indicating low agglomerates, approximately uniform pores and narrow pore‐size distribution 41,43 .…”

Sustainable Porous Heterogeneous Catalysts for the Conversion of Biomass into Renewable Energy Products

“…Inorganic porous materials are predominantly made of inorganic precursors with moderate to high surface area, versatile pore size distribution, feasible synthetic strategies, high chemical, and thermal stability making these materials more robust. 85 These materials could be utilized in the field of heterogeneous catalysis, photo-catalysis, toxic ion separation, adsorption, molecular sieving, etc. A great breakthrough came when ordered mesoporous silicas M41S 86 and SBA 87 type materials came into existence by a soft templating synthetic route, which are extensively explored nowadays.…”

“…Inorganic porous materials are predominantly made of inorganic precursors with moderate to high surface area, versatile pore size distribution, feasible synthetic strategies, high chemical, and thermal stability making these materials more robust . These materials could be utilized in the field of heterogeneous catalysis, photo-catalysis, toxic ion separation, adsorption, molecular sieving, etc .…”

Synthesis and Properties of Hybrid Silicas Containing Cetyltrialkylammoniun Surfactants

“…Devido à hidrofobicidade destas moléculas, essas podem ser incorporadas ao núcleo das micelas permitindo o aumento do diâmetro micelar. 11 De acordo com Beck et al, 12 é possível a obtenção da MCM-41 com diâmetro de poros de 7,5 nm através da adição de 20% em massa do 1,3,5-trimetilbenzeno no sistema reacional. Entretanto, salienta-se que a introdução de grandes quantidades de moléculas orgânicas para expansão das micelas não é considerada um procedimento viável, não somente por requerer uma quantidade razoável do composto orgânico e, consequentemente, um maior volume reacional, mas também por necessitar de procedimentos físicos adicionais para a separação dos agentes expansores além de seu reciclo para o sistema reacional.…”