Abstract: The invention is based on the preparation of an organic solution of preferably phosphonic acids and tetravalent metals salts, preferably of Zr, Ti, Sn and Ce, in organic solvents, which behaves as a solution of layered tetravalent metals salts, preferably phosphate-phosphonates, which are completely insoluble in the known solvents. This peculiarity allows an easy insertion of particles of the above compounds in the pores of porous membranes, in the matrices of those polymers, which are soluble in the same organic solvents, as well as in the membrane/electrode interfaces of fuel cells. The use of tetravalent metals salts, preferably zirconium phosphate-phosphonates, possessing high proton conductivity (in some cases higher than 10?1 S cm?1) allows the preparation of impregnated porous membranes and of nano-polymeric membranes combining good mechanical properties, and/or reduced permeability to gaseous species, with good proton conductivity.

Abstract: This invention is based on the preparation of new solid acid triphosphates with compositions of the general formula M(IV)(HPO4)(H2PO4)2, where M(IV) is a tetravalent metal or a mixture of tetravalent metals. These compounds are insoluble in water the greater part of most organic solvents. They show a high non-water assisted protonic conductivity (about 0.01-0.04 S/cm at 100° C. and a relative humidity lower than 1%). These compounds can be used as proton conduction separators in electrochemical devices, to operate at low relative humidity values, as for example in different fuel cells, protonic pumps for electrochemical hydrogenation and dehydrogenation of organic compounds, or for hydrogen production from hydrogenated organic compounds by electro-reforming, or also for removing hydrogen from equilibrium reactions. These compounds can also be used in electrochemical sensors, in super capacitors and as acid catalysts in non-aqueous or anhydrous gaseous phases.

Abstract: The invention is based on the preparation of precursor organic solutions of tetravalent metal phosphates and pyrophosphates with composition M(IV)(O3P—H)2, M(IV)[O2P(OH)2]2[O2PO(OH)] and M(IV)P2O7(M=Zr, Hf, Ti). An important property of these solutions is that the said compounds are formed when the solvent is evaporated. This peculiarity allows an easy insertion of the compounds inside the pores of porous membranes, in polymeric membranes and in the electrodic interfaces of fuel cells. The acid properties of their surfaces, the high thermal stability and the insolubility in water make these particles extremely of interest for improving the efficiency of PEMFCs in the temperature range 90-130° C. The peculiar characteristics of non-water assisted proton conductivity of M(IV)[O2P(OH)2]2[O2PO(OH)] compounds open new prospects for their application in PEMFCs at low relative humidity.

Abstract: The invention is relative to a membrane-electrode assembly for fuel cells, comprising a state of the art ion-exchange polymeric membrane and state of the art gas diffusion electrodes, whose electrochemical properties are modified through the addition of a hydrophilic component localized in correspondence to one or both the electrodic interfaces and/or one or both the external surfaces of the membrane. The modified membrane-electrode assembly is characterized by high protonic conductivity and high efficiency even in the presence of small quantities of carbon monoxide, or of other contaminants contained in the fuel, even at temperatures as low as 100° C., being also suitable for medium temperature (100–160° C.) operation at relative humidity level lower than saturation.

Abstract: The invention provides composite membrane materials comprising a polymer of the state of art uniformly filled with a zirconium phosphate, preferably ?-zirconium phosphate or zirconium phosphate sulfoarylenphosphonate particels. The composite membrane materials are preferably prepared starting from a solution of a polymer of the state of art and from a colloidal dispersion of ?-zirconium phosphate or a zirconium phosphate sulfoarylenphosphonate. The colloidal particles are transferred into the solution of the polymer preferably by mixing the dispersion with the solution or by means of phase transfer. The membrane material is preferably obtained by removing the solvent by evaporation or by a suitable non-solvent.

Abstract: This invention is based on the preparation of new solid acid triphosphates with compositions of the general formula M(IV)(HPO4)(H2PO4)2, where M(IV) is a tetravalent metal or a mixture of tetravalent metals. These compounds are insoluble in water the greater part of most organic solvents. They show a high non-water assisted protonic conductivity (about 0.01-0.04 S/cm at 100° C. and a relative humidity lower than 1%). These compounds can be used as proton conduction separators in electrochemical devices, to operate at low relative humidity values, as for example in different fuel cells, protonic pumps for electrochemical hydrogenation and dehydrogenation of organic compounds, or for hydrogen production from hydrogenated organic compounds by electro-reforming, or also for removing hydrogen from equilibrium reactions. These compounds can also be used in electrochemical sensors, in super capacitors and as acid catalysts in non-aqueous or anhydrous gaseous phases.

Abstract: The invention is based on the preparation of an organic solution of preferably phosphonic acids and tetravalent metals salts, preferably of Zr, Ti, Sn and Ce, in organic solvents, which behaves as a solution of layered tetravalent metals salts, preferably phosphate-phosphonates, which are completely insoluble in the known solvents. This peculiarity allows an easy insertion of particles of the above compounds in the pores of porous membranes, in the matrices of those polymers, which are soluble in the same organic solvents, as well as in the membrane/electrode interfaces of fuel cells. The use of tetravalent metals salts, preferably zirconium phosphate-phosphonates, possessing high proton conductivity (in some cases higher than 10?1 S cm?1) allows the preparation of impregnated porous membranes and of nano-polymeric membranes combining good mechanical properties, and/or reduced permeability to gaseous species, with good proton conductivity.

Abstract: The invention provides composite membrane materials comprising a polymer of the state of art uniformly filled with a zirconium phosphate, preferably ?-zirconium phosphate or zirconium phosphate sulfoarylenphosphonate particels. The composite membrane materials are preferably prepared starting from a solution of a polymer of the state of art and from a colloidal dispersion of ?-zirconium phosphate or a zirconium phosphate sulfoarylenphosphonate. The colloidal particles are transferred into the solution of the polymer preferably by mixing the dispersion with the solution or by means of phase transfer. The membrane material is preferably obtained by removing the solvent by evaporation or by a suitable non-solvent.

Abstract: The invention is relative to a membrane-electrode assembly for fuel cells, comprising a state of the art ion-exchange polymeric membrane and by state of the art gas diffusion electrodes, whose electrochemical properties are modified through the addition of a hydrophilic component localized in correspondence of one or both the electrodic interfaces and/or one or both the external surfaces of the membrane. The such modified membrane-electrode assembly is characterised by high protonic conductivity and high efficiency even in the presence of small quantities of carbon monoxide, or of other contaminants contained in the fuel, even at temperatures as low as 100° C., being also suitable for medium temperature (100-160° C.) operation at relative humidity level lower than saturation.

Abstract: Solid mesoporous crystalline composition of a pyrophosphate-phosphate of a tetravalent metal, with a high surface area and narrow distribution of the mesopores, having formula (I):M(P.sub.2 O.sub.7).sub.1-z (HPO.sub.4).sub.2z (I)wherein: M is a tetravalent metal and z varies from 0.05 to 0.25.The process for its production is described together with its uses.

Abstract: Solid mesoporous crystalline composition of diphospho-nate-phosphite of a tetravalent metal, with a limited distribution of mesopores having the formulaM?(O.sub.3 P--R--PO.sub.3).sub.1-x-y (HPO.sub.3).sub.2x (O.sub.3 P--R--PO.sub.3 H.sub.2).sub.2y !wherein: M is a tetravalent metal, R is a bivalent organic radical, x varies from 0.3 to 0.6, y varies from 0.05 to 0.3. The process for its production is described, together with its uses and a solid catalyst containing --SO.sub.3 H acid groups, active in the conversion processes of hydrocarbons, which can be obtained from said mesoporous crystalline composition by treatment with a sulfonicphosphonic or arylphosphonic acid, followed, only in the case of treatment with arylphosphonic acid, by sulfonation with a sulfonating agent.

Abstract: A sensor in completely solid state for determining the concentration of a gas, in particular of hydrogen, is disclosed, which is essentially constituted by electrodes separated by a protonic conductor in the solid state, in which the solid-state reference electrode is constituted by a metal hydride, or a metal-alloy hydride.

Abstract: A solid-state sensor device for determining the concentration of gases which can react with hydrogen, in particular oxygen, is disclosed, which is essentially composed of a solid-state protonic conductor put into contact, at one of its sides, with a reference electrode and, at its other side, with a composite electrode (sensor electrode), constituted by a catalytic material into contact with a hydride of a metal or of a metal alloy.

Abstract: A tetravalent metal diphosphonate-phosphite composition definable by the following general formula:M(O.sub.3 P--R--PO.sub.3).sub.1-x (HPO.sub.3).sub.2x (I)is described where:M is a tetravalent metal;x varies from 0.5 to 0.66;R is an organic radical of bivalent aromatic type, carrying side groups which increase its steric hindrance.The composition is in the form of a crystalline solid with a type .alpha. layered structure with the diphosphonic groups positioned to join said layers together by a covalent bond (pillared compounds). It has a B.E.T. surface area from 300 to 500 m.sup.2 /g depending on the nature of R in formula (I), and a porosity in the micropore radius range of less than 20 .ANG. (Angstrom), such micropores contributing to the extent of more than 95% of the total area for the most crystalline materials.

Abstract: The present invention discloses a compound comprising a diphosphonate/phosphite of a tetravalent metal:M[(O.sub.3 P--R--PO.sub.3).sub.1-(x+y) (HPO.sub.3).sub.2X (O.sub.3 P--R--PO.sub.3 H.sub.2).sub.2y ](where M, R, x and y have the meaning given in the description), in the form of a crystalline solid with an alpha-type lamellar structure with a distance between layers of 7.4 to 20.ANG. (depending on the dimensions of radical R), a BET surface area of 250 to 400m.sup.2 /g, and porosity within the mesopore range, with at least 50% of the pores measuring 20 to 30.ANG.. The compound, depending on the radical R used, may or may not have microporosity in the region between layers. Such a diphosphonate/phosphite of a tetravalent metal is obtained by reaction between diphosphonic acid, phosphorous acid and an oxyhalide of a tetravalent metal, in a solvent comprising dimethyl-sulphoxide/water containing hydrofluoric acid.

Abstract: A solid-state sensor for determining the concentration of gases which can react with hydrogen, in particular, of oxygen, which includes a solid-state proton conductor into contact: on the one side, with a reference electrode, constituted in its turn by a metal hydride or a metal alloy, and on the other side with an electrode which catalyses the reaction of the gas to be detected, with said sensor being connected with a power feed system which supplies current or voltage impulses, and with a system which detects the value of potential after each impulse.

Abstract: Disclosed is a solid catalyst functionalized with sulfonic groups, containing from 20 to 99% by weight of silica, with the residual percentage being definable by means of the formula:(ZrP.sub.2 O.sub.7).sub.1-x {(Zr(HPO.sub.4).sub.2-y.[O.sub.3 P-R(SO.sub.3 H).sub.n ].sub.y }.sub.xwherein:R is an either linear or branched linear hydrocarbon radical containing from 1 to 10 carbon atoms, or an aryl radical;x is a numeral higher than 0 and of up to 1;y is a numeral higher than 0 and of up to 2;n is either 1 or 2;with said catalyst furthermore showing silicon-oxygen-phosphorus bonds on N.M.R. examination and being amorphous or substantially amorphous when examined under X rays.The catalyst is useful in the acidic catalysis, for example in reactions of hydrocarbon conversion, such as alkylation, isomerization and oligomerization. The product according to the present invention is furthermore useful as an ion exchange agent.

Abstract: The invention relates to a zirconium phosphate in particles having sizes comprised within the range of from 1 to 100 .mu.m, a lamellar structure with interlayer distance, in the anhydrous state, comprised within the range of from 7.9 to 8.2 .ANG. and a surface area comprised within the range of from 9 to 20 m.sup.2 /g.The method consists in altering the lamellar structure of a zirconium phosphate with layer structure of alpha type by intercalating into it an organic substance containing a proton-acceptor group and water and by a treatment with ultrasounds, in regenerating the hydrogen form of said zirconium phosphate by an acid and in washing the same with diluted acids and/or water.

Abstract: Ion exchange inorganic films made up of alpha-type or gamma-type layered structure insoluble acid salts of tetravalent metals or their salt forms, or their intercalated forms or their organic derivatives containing polar groups. A process for the preparation of said films.

Abstract: Mixed phosphorous or arsenic salts of tetravalent metals are provided having the general formula M(HAO.sub.4).sub.2-x (HAO.sub.3).sub.x.nH.sub.2 O, where M is Zr, Ti or Hf, A is phosphorus or arsenic, x is between 0.05 and 1.95, and n is 0 to 6. The salts are highly stable and have wide potential application in the fields of ion exchange, catalysis, intercalation of molecules, solid electrolytes, and chromatography. The salts are prepared by reacting a halide, oxyhalide, nitrate, sulphate, phosphate or oxide of the tetravalent metal, preferably in an aqueous medium, with at least two oxygenated acids of phosphorus and/or arsenic.