Electron microscopy images of nitrogen-containing ordered mesoporous carbon (N-OMC) taken (a) along and (b) perpendicular to the channel direction.[1]
Amesoporous material (or super nanoporous[2]) is ananoporous material containingpores with diameters between 2 and 50 nm, according toIUPAC nomenclature.[3][4] For comparison, IUPAC definesmicroporous material as a material having pores smaller than 2 nm in diameter andmacroporous material as a material having pores larger than 50 nm in diameter.
Typical mesoporous materials include some kinds ofsilica andalumina that have similarly-sized mesopores. Mesoporous oxides ofniobium,tantalum,titanium,zirconium,cerium andtin have also been reported. However, the flagship of mesoporous materials is mesoporous carbon, which has direct applications in energy storage devices.[5] Mesoporous carbon has porosity within the mesopore range and this significantly increases the specific surface area. Another very common mesoporous material isactivated carbon which is typically composed of a carbon framework with both mesoporosity and microporosity depending on the conditions under which it was synthesized.
According to IUPAC, a mesoporous material can be disordered or ordered in a mesostructure. In crystalline inorganic materials, mesoporous structure noticeably limits the number of lattice units, and this significantly changes the solid-state chemistry. For example, the battery performance of mesoporous electroactive materials is significantly different from that of their bulk structure.[6]
A procedure for producing mesoporous materials (silica) was patented around 1970,[7][8][9] and methods based on theStöber process from 1968[10] were still in use in 2015.[11] It went almost unnoticed[12] and was reproduced in 1997.[13] Mesoporous silicananoparticles (MSNs) were independently synthesized in 1990 by researchers in Japan.[14] They were later produced also at Mobil Corporation laboratories[15] and namedMobil Crystalline Materials, or MCM-41.[16] The initial synthetic methods did not allow to control the quality of the secondary level of porosity generated. It was only by employingquaternary ammonium cations andsilanization agents during the synthesis that the materials exhibited a true level of hierarchical porosity and enhanced textural properties.[17][18] Mesoporous materials have been also produced in the form of thin films via evaporation induced self-assembly, in different organized mesostructures and compositions.[19]
Since then, research in this field has steadily grown. Notable examples of prospective industrial applications arecatalysis, sorption, gas sensing, batteries,[20] ion exchange,optics, andphotovoltaics. In the field of catalysis, zeolites is an emerging topic where the mesoporosity as a function of the catalyst is studied to improve its performance for use inFluid catalytic cracking.
It should be taken into account that this mesoporosity refers to the classification of nanoscale porosity, and mesopores may be defined differently in other contexts; for example, mesopores are defined as cavities with sizes in the range 30 μm–75 μm in the context of porous aggregations such as soil.[21]
^Eftekhari, Ali; Zhaoyang, Fan (2017). "Ordered mesoporous carbon and its applications for electrochemical energy storage and conversion".Materials Chemistry Frontiers.1 (6):1001–1027.doi:10.1039/C6QM00298F.
^Chiola, V.; Ritsko, J. E. and Vanderpool, C. D."Process for producing low-bulk density silica." Application No. US 3556725D A filed on 26-Feb-1969; Publication No. US 3556725 A published on 19-Jan-1971
^Beck, J. S.; Vartuli, J. C.; Roth, W. J.; Leonowicz, M. E.; Kresge, C. T.; Schmitt, K. D.; Chu, C. T. W.; Olson, D. H.; Sheppard, E. W. (1992). "A new family of mesoporous molecular sieves prepared with liquid crystal templates".Journal of the American Chemical Society.114 (27): 10834.Bibcode:1992JAChS.11410834B.doi:10.1021/ja00053a020.
^Perez-Ramirez, J.; Christensen, C. H.; Egeblad, K.; Christensen, C. H.; Groen, J. C. (2008). "Hierarchical zeolites: enhanced utilisation of microporous crystals in catalysis by advances in materials design".Chem. Soc. Rev.37 (11):2530–2542.doi:10.1039/b809030k.PMID18949124.
^Perez-Ramirez, J.; Verboekend, D. (2011). "Design of hierarchical zeolite catalysts by desilication".Catal. Sci. Technol.1 (6):879–890.doi:10.1039/C1CY00150G.hdl:20.500.11850/212833.
^Innocenzi, Plinio (2022).Mesoporous ordered silica films. From self-assembly to order. Springer.ISBN978-3-030-89535-8.
^Stein, Andreas (2020). Gitis, Vitaly; Rothenberg, Gadi (eds.).Handbook of Porous Materials. Vol. 4. Singapore: WORLD SCIENTIFIC.doi:10.1142/11909.ISBN978-981-12-2322-8.
