It is possible to say that zeolites are the most widely used catalysts in industry They are crystalline microporous materials which have become extremely successful as catalysts for oil refining, petrochemistry, and organic synthesis in the production of fine and speciality chemicals, particularly when dealing with molecules having kinetic diameters below 10 A The reason for their success in catalysis is related to the following specific features of these materials:1 (1) They have very high surface area and adsorption capacity (2) The adsorption properties of the zeolites can be controlled, and they can be varied from hydrophobic to hydrophilic type materials (3) Active sites, such as acid sites for instance, can be generated in the framework and their strength and concentration can be tailored for a particular application (4) The sizes of their channels and cavities are in the range typical for many molecules of interest (5-12 A), and the strong electric fields2 existing in those micropores together with an electronic confinement of the guest molecules3 are responsible for a preactivation of the reactants (5) Their intricate channel structure allows the zeolites to present different types of shape selectivity, ie, product, reactant, and transition state, which can be used to direct a given catalytic reaction toward the desired product avoiding undesired side reactions (6) All of these properties of zeolites, which are of paramount importance in catalysis and make them attractive choices for the types of processes listed above, are ultimately dependent on the thermal and hydrothermal stability of these materials In the case of zeolites, they can be activated to produce very stable materials not just resistant to heat and steam but also to chemical attacks Avelino Corma Canos was born in Moncofar, Spain, in 1951 He studied chemistry at the Universidad de Valencia (1967−1973) and received his PhD at the Universidad Complutense de Madrid in 1976 He became director of the Instituto de Tecnologia Quimica (UPV-CSIC) at the Universidad Politecnica de Valencia in 1990 His current research field is zeolites as catalysts, covering aspects of synthesis, characterization and reactivity in acid−base and redox catalysis A Corma has written about 250 articles on these subjects in international journals, three books, and a number of reviews and book chapters He is a member of the Editorial Board of Zeolites, Catalysis Review Science and Engineering, Catalysis Letters, Applied Catalysis, Journal of Molecular Catalysis, Research Trends, CaTTech, and Journal of the Chemical Society, Chemical Communications A Corma is coauthor of 20 patents, five of them being for commercial applications He has been awarded with the Dupont Award on new materials (1995), and the Spanish National Award “Leonardo Torres Quevedo” on Technology Research (1996) 2373 Chem Rev 1997, 97, 2373−2419

From Microporous to Mesoporous Molecular-Sieve Materials and Their Use in Catalysis

Organic–inorganic hybrid materials do not represent only a creative alternative to design new materials and compounds for academic research, but their improved or unusual features allow the development of innovative industrial applications. Nowadays, most of the hybrid materials that have already entered the market are synthesised and processed by using conventional soft chemistry based routes developed in the eighties. These processes are based on: a) the copolymerisation of functional organosilanes, macromonomers, and metal alkoxides, b) the encapsulation of organic components within sol–gel derived silica or metallic oxides, c) the organic functionalisation of nanofillers, nanoclays or other compounds with lamellar structures, etc. The chemical strategies (self-assembly, nanobuilding block approaches, hybrid MOF (Metal Organic Frameworks), integrative synthesis, coupled processes, bio-inspired strategies, etc.) offered nowadays by academic research allow, through an intelligent tuned coding, the development of a new vectorial chemistry, able to direct the assembling of a large variety of structurally well defined nano-objects into complex hybrid architectures hierarchically organised in terms of structure and functions. Looking to the future, there is no doubt that these new generations of hybrid materials, born from the very fruitful activities in this research field, will open a land of promising applications in many areas: optics, electronics, ionics, mechanics, energy, environment, biology, medicine for example as membranes and separation devices, functional smart coatings, fuel and solar cells, catalysts, sensors, etc.

Applications of hybrid organic–inorganic nanocomposites

The state-of-the-art of polymer electrolyte membrane fuel cell (PEMFC) technology is based on perfluorosulfonic acid (PFSA) polymer membranes operating at a typical temperature of 80 °C. Some of the key issues and shortcomings of the PFSA-based PEMFC technology are briefly discussed. These include water management, CO poisoning, hydrogen, reformate and methanol as fuels, cooling, and heat recovery. As a means to solve these shortcomings, high-temperature polymer electrolyte membranes for operation above 100 °C are under active development. This treatise is devoted to a review of the area encompassing modified PFSA membranes, alternative sulfonated polymer and their composite membranes, and acid−base complex membranes. PFSA membranes have been modified by swelling with nonvolatile solvents and preparing composites with hydrophilic oxides and solid proton conductors. DMFC and H2/O2(air) cells based on modified PFSA membranes have been successfully operated at temperatures up to 120 °C under ambient pressure...

/pdf/approaches-and-recent-development-of-polymer-electrolyte-1glbhokzz9.pdf

Approaches and Recent Development of Polymer Electrolyte Membranes for Fuel Cells Operating above 100 °C

Structural diversity and chemical trends in hybrid inorganic–organic framework materials

Cleḿence Queffeĺec,† Marc Petit,†,‡ Pascal Janvier,† D. Andrew Knight, and Bruno Bujoli*,† †LUNAM Universite,́ CNRS, UMR 6230, Chimie Et Interdisciplinarite:́ Synthes̀e Analyse Modeĺisation (CEISAM), UFR Sciences et Techniques, 2, rue de la Houssinier̀e, BP 92208, 44322 NANTES Cedex 3, France ‡Universite ́ Pierre et Marie Curie (UPMC), CNRS, UMR7201, Institut Parisien De Chimie Molećulaire (IPCM), 4 place Jussieu, 75252 Paris Cedex 05, France Chemistry Department, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, United States

Surface modification using phosphonic acids and esters.

Crystalline Zr(R-PO3)2 and Zr(R-OPO3)2 compounds (R = organic radical)

Preparation and ion-exchange properties of a new phase of the crystalline titanium phosphate, Ti(HPO4)2·2H2O

Crystalline insoluble acid salts of tetravalent metals—XX Forward and reverse Cs+/H+ and Rb+/H+ ion exchange on crystalline zirconium phosphate

A series of transition-metal-ion forms of crystalline zirconium phosphate of general formula ZrM(PO4)2·4H2O (M = ZnII, CuII, NiII, CoII, and MnII) has been characterised. The visible–near U.V. spectra of the copper, nickel, and cobalt species indicate the presence of an octahedral stereochemistry (tetragonally distorted in the case of CuII). The dehydration of the exchangers has been followed using thermal and X-ray powder techniques and electronic spectra. Magnetic-susceptibility measurements have also been used (where possible) to support structural assignment. Complete dehydration occurs only atca. 450 °C with a change in stereochemistry for the compounds of NiII and CoII. At higher temperature the layer structure is lost and the materials become double phosphates, MZr(PO4)2. Possible stereochemistries for the anhydrous forms are discussed.

S. Allulli

Papers

Crystalline Zr(R-PO3)2 and Zr(R-OPO3)2 compounds (R = organic radical)

Preparation and ion-exchange properties of a new phase of the crystalline titanium phosphate, Ti(HPO4)2·2H2O

Crystalline insoluble acid salts of tetravalent metals—XX Forward and reverse Cs+/H+ and Rb+/H+ ion exchange on crystalline zirconium phosphate

Characterisation and electronic properties of some inorganic ion exchangers of the zirconium phosphate type containig transition-metal ions

Uptake of transition metal ions by crystalline zirconium phosphate