Makoto Misono

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeterogeneous CatalysisNoritaka Mizuno and Makoto MisonoView Author Information Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan Cite this: Chem. Rev. 1998, 98, 1, 199–218Publication Date (Web):January 8, 1998Publication History Received3 May 1997Revised2 September 1997Published online8 January 1998Published inissue 1 February 1998https://pubs.acs.org/doi/10.1021/cr960401qhttps://doi.org/10.1021/cr960401qresearch-articleACS PublicationsCopyright © 1998 American Chemical SocietyRequest reuse permissionsArticle Views17164Altmetric-Citations1889LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Catalysts,Hydrogen,Oxidation,Redox reactions,Salts Get e-Alerts

Abstract Heteropolyanions are polymeric oxoanions which are formed by the condensation of more than two different oxoanions [Eq. (1)l. Polyanions consisting of one kind of oxoanion are called isopolyanions [Eq. (2)]. Acidic elements such as Mo, W, V, Nb, and Ta are present as oxoanions in aqueous solutions and polymerize to form polyanions at low pH. Free acids (or acid forms) of these species are called heteropoly and isopoly acids, respectively. Here, the term “heteropoly compounds” is used for heteropoly acids and their salts.

Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films, and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol−gel-derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

Fundamental and superior characteristics of heteropoly compounds (heteropolyoxometalates) in the solid state that make them suitable for catalyst design at the atomic/molecular levels are described, together with important principles required for the understanding and design of solid heteropoly catalysts. First, the molecular nature of heteropolyanions (metal oxide clusters), which can be preserved in the solid state, enables control of the acid and redox properties over a wide range. Second, the presence of hierarchical structures (primary, secondary and tertiary structures) can lead to three catalysis modes—surface-type, pseudoliquid (or bulk-type I) and bulk-type II. Precise control of pore size is possible through the understanding of the microstructure, which results in unique shape selectivity observed for various reactions. Heteropoly compounds are green catalysts functioning in a variety of reaction fields and efficient bifunctional catalysts when combined with other components. The elucidation of catalytic processes is also possible at the atomic/molecular level due to their molecular nature. The positions and dynamic nature of protons as well as organic reaction intermediates in the pseudo-liquid phase can be clarified by spectroscopic techniques. Various reactions promoted by solid heteropoly catalysts are collected from recent publications to illustrate the usefulness of the above ideas and of heteropoly catalysts themselves.