CATALYSIS WITH ISOLATED METAL ATOMS AND WELL-DEFINED ULTRASMALL CLUSTERS, WITHOUT LIGANDS AND CONFINED. (Q3135804)
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Project Q3135804 in Spain
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | CATALYSIS WITH ISOLATED METAL ATOMS AND WELL-DEFINED ULTRASMALL CLUSTERS, WITHOUT LIGANDS AND CONFINED. |
Project Q3135804 in Spain |
Statements
39,325.0 Euro
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78,650.0 Euro
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50.0 percent
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1 January 2018
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31 December 2020
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AGENCIA CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
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39°28'10.96"N, 0°22'34.82"W
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46250
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LA CATALISIS QUIMICA SOBRE ATOMOS METALICOS INSATURADOS ES LA BASE DE UNA BUENA PARTE DE LOS PROCESOS INDUSTRIALES DE GENERACION DE ENERGIA Y SINTESIS QUIMICA, Y TAMBIEN DE MUCHAS REACCIONES ESENCIALES PARA LA VIDA. TRADICIONALMENTE, LA ACTIVIDAD CATALITICA DEL ATOMO METALICO ES MODULADA POR LA ACCION DEL SOPORTE, DE LIGANDOS, O POR LA ACCION CONJUNTA DE OTROS MUCHOS ATOMOS METALICOS (NANOPARTICULAS). SIN EMBARGO, SON CADA VEZ MAS LOS TRABAJOS EXPERIMENTALES QUE DEMUESTRAN QUE ATOMOS METALICOS AISLADOS O EN UN NUMERO MUY BAJO, MENOS DE 10 ATOMOS, SON EXCELENTES CATALIZADORES PARA UNA GRAN VARIEDAD DE REACCIONES QUIMICAS, SIN LA NECESIDAD DE SOPORTES, LIGANDOS U OTROS ADITIVOS EXTERNOS._x000D_ HASTA LA FECHA, ESTOS CATALIZADORES BASAN SU SINTESIS EN LA DILUCION, ES DECIR, EN LA MAYOR SEPARACION POSIBLE DE LOS ATOMOS METALICOS, BIEN SOBRE SUPERFICIES INERTES O EN DISOLUCION, PARA EVITAR SU AGREGACION Y CON CANTIDADES METALICAS MENORES AL 0.1% EN PESO. AUNQUE LOS ESTUDIOS DEJAN CLARO QUE LA ACTIVIDAD CATALITICA PROVIENE EXCLUSIVAMENTE DE LAS ESTRUCTURAS ULTAPEQUEÑAS, INCLUSO ATOMOS AISLADOS, EXPERIMENTALMENTE ES IMPOSIBLE SABER CON EXACTITUD EL NUMERO DE ATOMOS, ESTADO DE OXIDACION Y TOPOLOGIA DE LAS ESPECIES CATALITICAS, SENCILLAMENTE PORQUE LA CONCENTRACION DE ESPECIES ES TAN BAJA QUE LAS TECNICAS EXPERIMENTALES MAS AVANZADAS TALES COMO LA MICROSOCOPIA DE ABERRACION CORREGIDA, FOTOESPECTROMETRIA DE RAYOS X O TECNICAS SINCROTRON NO PERMITEN RESOLVER LAS ESTRUCTURAS ADECUADAMENTE. POR TANTO, LA ACTIVIDAD CATALITICA ESPECIFICA DE ATOMOS AISLADOS Y CLUSTERES DEFINIDOS ES AUN UN DESAFIO PARA LA CIENCIA._x000D_ RECIENTEMENTE, HEMOS DESCRITO QUE CIERTAS REDES METAL-ORGANICAS ("METAL ORGANIC FRAMEWORKS", MOFS, POR SUS SIGLAS EN INGLES) SON CAPACES DE INCOPORAR HASTA UN 15% EN PESO DE ATOMOS METALICOS Y, POR EJEMPLO, FORMAR CLUSTERES METALICOS DE CUATRO ATOMOS DE PALADIO, CATALITICOS, DE VALENCIA MIXTA 0/+1, CUASI-LINEALES Y CONFINADOS, CON PROPIEDADES ELECTRONICAS Y ESTRUCTURALES PERFECTAMENTE DEFINIDAS Y SIN CONTAMICION DE OTRAS ESPECIES, YA QUE SE OBTIENEN EN FORMA CRISTALINA Y SE CARACTERIZAN PERFECTAMENTE NO SOLO MEDIANTE LAS TECNICAS ARRIBA NOMBRADAS SINO TAMBIEN POR CRISTALOGRAFIA DE RAYOS X Y POR CALCULOS TEORICOS. POR TANTO, AHORA PODEMOS REALIZAR UN ESTUDIO SISTEMATICO DE LA ACTIVIDAD CATALITICA DE DIFERENTES ATOMOS METALICOS AISLADOS Y CLUSTERES ULTRAPEQUEÑOS PERFECTAMENTE DEFINIDOS, LIBRES DE LIGANDOS Y SIN INTERACCIONES FUERTES CON EL SOPORTE. ESTE ESTUDIO FUNDAMENTAL ES TOTALMENTE NOVEDOSO Y TAMBIEN CON POTENCIAL APLICACION PRACTICA PARA SU POSTERIOR UTILIZACION EN PROCESOS DE INTERES, INDUSTRIALES O BIOMIMETICOS. PARA ELLO, SE INCORPORARAN Y CARACTERIZARAN DIVERSOS CATIONES METALICOS EN LOS MOFS Y SE REDUCIRAN CONTROLADAMENTE PARA OBTENER ATOMOS AISLADOS O CLUSTERES DE CRECENTE ATOMICIDAD HASTA DIEZ ATOMOS, PARA SU EVALUACION CATALITICA. FINALMENTE, ESTAS ESPECIES METALICAS ULTRAPEQUEÑAS SE COMPARARAN CON OTRAS ESTRUTURAS CATALITICAS METALICAS NO TAN BIEN DEFINIDAS, COMO METALES SOBRE ZEOLITAS, SOLIDOS INORGANICOS Y POLIMEROS, Y TAMBIEN CATALIZADORES ORGANOMETALICOS Y SALES METALICAS QUE SE SABE DESCOMPONEN IN-SITU DURANTE REACCION, Y DONDE SE SOSPECHA QUE LAS ESPECIES ACTIVAS SON ATOMOS AISLADOS O CLUSTERES. POR CARACTERIZACION Y REACTIVIDAD COMPARADA, PODREMOS AHORA CONFIRMAR LA ACTIVIDAD DE LAS ESPECIES ULTRAPEQUEÑAS EN LOS CATALIZADORES NO TAN BIEN DEFINIDOS Y PROCEDER A SU OPTIMIZACION. (Spanish)
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CHEMICAL CATALYSIS ON UNSATURATED METAL ATOMS IS THE BASIS OF MUCH OF THE INDUSTRIAL PROCESSES ON ENERGY GENERATION AND CHEMICAL SYNTHESIS, AND ALSO OF MANY ESSENTIAL REACTIONS FOR LIFE. TRADITIONALLY, THE CATALYTIC ACTIVITY OF THE METAL ATOM IS MODIFIED BY THE ACTION OF A SUPPORT, LIGANDS, OR BY THE JOINT ACTION OF OTHER METAL ATOMS (NANOPARTICLES). HOWEVER, THEY ARE INCREASINGLY EXPERIMENTAL WORKS WHICH SHOW THAT METAL ATOMS, ISOLATED OR IN VERY SMALL NUMBER, LESS THAN 10 ATOMS, ARE EXCELLENT CATALYSTS FOR A WIDE VARIETY OF CHEMICAL REACTIONS, WITHOUT THE NEED FOR ANY OTHER EXTERNAL ADDITIVE._x000D_ TO DATE, THESE CATALYSTS BASED ITS SYNTHESIS IN THE DILUTION, I.E., GREATER SEPARATION OF THE METAL ATOMS BY USING EITHER INERT SURFACES OR DISSOLUTION, IN ORDER TO PREVENT THEIR AGGREGATION, WICH LEADS TO TYPICAL METAL AMOUNTS LESS THAN 0.1% BY WEIGHT. ALTHOUGH STUDIES HAVE MADE IT CLEAR THAT THE CATALYTIC ACTIVITY IS DERIVED EXCLUSIVELY FROM THE ULTRASMALL STRUCTURES, OR EVEN FROM ISOLATED ATOMS, IT IS EXPERIMENTALLY IMPOSSIBLE TO KNOW EXACTLY THE NUMBER OF ATOMS, OXIDATION STATE AND TOPOLOGY OF THE CATALYTICALLY ACTIVE SPECIES, SIMPLY BECAUSE THE CONCENTRATION OF SPECIES IS SO LOW THAT THE MORE ADVANCED EXPERIMENTAL TECHNIQUES SUCH AS ABERRATION CORRECTED MICROSCOPY, X-RAY PHOTOSPECTROMETRY OR SYNCHROTRON TECHNIQUES DO NOT ALLOW TO SOLVE THE STRUCTURES PROPERLY. THEREFORE, THE SPECIFIC CATALYTIC ACTIVITY OF ISOLATED ATOMS AND DEFINED-CLUSTERS IS STILL A CHALLENGE FOR SCIENCE._x000D_ RECENTLY, WE HAVE DESCRIBED SOME METAL-ORGANIC NETWORKS ("METAL ORGANIC FRAMEWORKS", MOFS, FOR ITS ACRONYM IN ENGLISH) CAPABLE OF MEASURING UP TO 15% BY WEIGHT OF METAL ATOMS AND, FOR EXAMPLE, FORMING A CATALYTIC, 0/+1 MIXED VALENCE, QUASI-LINEAR AND CONFINED CLUSTER OF FOUR PALLADIUM ATOMS, WITH PERFECTLY DEFINED ELECTRONIC AND STRUCTURAL PROPERTIES AND WITHOUT ANY CONTAMINATION BY OTHER SPECIES, SINCE THEY ARE OBTAINED IN CRYSTALLINE FORM AND ARE PERFECTLY CHARACTERIZED NOT ONLY BY THE TECHNIQUES NAMED ABOVE BUT ALSO BY X-RAY CRYSTALLOGRAPHY AND BY THEORETICAL CALCULATIONS. THEREFORE, WE CAN NOW MAKE A SYSTEMATIC STUDY OF THE CATALYTIC ACTIVITY OF PERFECTLY DEFINED, LIGAND-FREE ISOLATED METAL ATOMS AND CLUSTERS, WITHOUT STRONG INTERACTIONS FROM THE SUPPORT. THIS PIVOTAL STUDY IS TOTALLY NEW AND ALSO WITH POTENTIAL PRACTICAL APPLICATION FOR SUBSEQUENT USE IN INDUSTRIAL OR BIOMIMETIC PROCESSES OF INTEREST. TO DO SO, THE INCORPORATION AND CHARACTERIZATION OF VARIOUS METAL CATIONS IN THE MOFS WILL BE CARRIED OUT, AND THEN REDUCTION IN A CONTROLLED WAY TO OBTAIN WELL-DEFINED ISOLATED ATOMS OR METAL CLUSTERS OF CRECENT ATOMICITY, UNTIL TEN ATOMS, FOR COMPARATIVE CATALYTIC EVALUATION. FINALLY, THESE ULTRASMALL METAL SPECIES WILL BE COMPARED WITH NO SO-WELL DEFINED METAL CATALYSTS SUCH AS METALS ON ZEOLITES, INORGANIC SOLIDS AND POLYMERS, AND ALSO WITH ORGANOMETALLIC AND METAL SALT CATALYSTS THAT ARE KNOWN TO DECOMPOSE DURING REACTION, AND WHERE IT IS SUSPECTED THAT THE ACTIVE SPECIES ARE ISOLATED ATOMS OR CLUSTERS. BY COMPARISON OF THE CHARACTERIZATION AND REACTIVITY, IT WILL BE NOW POSSIBLE TO CONFIRM THE ACTIVITY OF THE ULTRASMALL METAL SPECIES AND OPTIMIZE THE CATALYSTS. (English)
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Valencia
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Identifiers
CTQ2017-86735-P
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