Rationalize the synthesis of zeolite catalysts by understanding reaction mechanism

[EN] The present thesis focuses on the rationalization of the zeolite synthesis for catalysis by understanding the nature of active sites and their microenvironments, together with their influence on the mechanisms of catalyzed reactions. In the first part of the thesis, efforts have been put on attempting to achieve the regioselective locating of active sites in zeolite catalyst and, more specifically, on tunning acid site locations in zeolite framework. The development of a zeolite synthesis strategy and an indicator that can describe the aluminum distribution in the zeolite framework is important to evaluate if the final objective has been achieved. In this part, in order to evaluate aluminum distribution in MFI framework, an indicator based on monomolecular and bimolecular mechanisms of n-hexene catalytic cracking was proposed. First, several ZSM-5 samples were synthesized, which have been reported in the literature to have different aluminum distributions. These samples were characterized to be analogous in physicochemical properties and, then, tested in the n-hexene cracking to justify the usefulness of the indicator proposed in this work. Using 27Al MAS NMR, the aluminum locations were proved to be different, which was also reflected by the indicator in this thesis, justifying its applicability to evaluate aluminum locations. Afterward, this indicator has been employed to check the zeolite synthesis methodology that could potentially lead to different aluminum distribution in zeolite frameworks. Then, a boron-assisted synthesis is proposed considering that boron and aluminum may have competitive positioning in ZSM-5 framework. Then, and by means of DFT calculations, we have studied if the unit cell of MFI shows different stabilities when substituted by aluminum and/or boron in different T positions. It has been found that boron location is less favored when introduced in 10-ring channels of the MFI framework, while aluminum shows no preference for positioning among all the T-sites. ZSM-5 samples with different Si/Al and Si/B were synthesized and their physicochemical properties as well as the relative proportion of paired and isolated states of aluminum was characterized. Characterization includes n-hexene cracking, for which the samples showed different preference toward monomolecular and bimolecular reactions. Finally, once the materials were proved to have different aluminum distribution, they were employed in methanol-to-propene (MTP) reactions to show the influence of aluminum distribution on an industry-relevant reaction where the spatial confinement has an important impact. Indeed, the samples with aluminum preferentially positioned in 10-ring channel favored more monomolecular cracking and less bimolecular side reactions such as oligomerization and hydrogen transfer, giving higher propene yield and lower amount of alkanes and aromatics. The second part of the thesis focuses on rationalizing the synthesis of zeolites with cavities for catalyzing “a priory” selected reaction. More specifically, zeolite synthesis was carried out using OSDAs that mimic the transition state (TS) or a relevant intermediate in the target reaction. Ethylbenzene production by transalkylation between diethylbenzene and benzene was selected as the reaction to be catalyzed. A potential reaction TS was established and a diaryldimethylphosphonium OSDA was synthesized that mimicks the transition state in the diaryl-mediated mechanism of transalkylation between benzene and diethylbenzene. Then, the OSDA successfully led to the formation of the largepore zeolite ITQ-27. This ITQ-27 was tested in the reaction of transalkylation between benzene and diethylbenzene. The catalytic performance of this material was benchmarked to be superior than other commercially employed zeolites, such as USY, mordenite or Beta with similar physicochemical properties. Finally, Methanol to olefins (MTO) reaction was chosen as another target catalytic system, where the reaction pathways are more complicated than transalkylation between benzene and diethylbenzene but nevertheless they have been well established in the literature. Thus, several OSDAs were synthesized mimicking the intermediates and transition states of the paring pathway, which produces more propene and butenes, which are highly demanded among all products. The OSDAs led to formation of several cage-based small pore zeolites, such as CHA, RTH and AEI. All the zeolites obtained were tested in MTO reactions to evaluate their catalytic activity and gave high selectivity toward light olefins, which appeared to selectively depend on the zeolite tested. The tendency of each structure toward certain product distributions was related to the reaction mechanism by establishing a structure-reactivity correlation, when the experiment results were combined with theoretical calculations. It is proposed that different shape of the cavities stabilize different precursor intermediates present in the paring or side-chain pathways and this indicates the reaction preference between each pathway and therefore the product distributions. A linear correlation was obtained between the shape of cavities and the C3 = /C2 = molar ratios being possible. In this way, ITQ-3 (ITE structure) was predicted that should also give higher selectivity toward paring pathway, which has been demonstrated experimentally[ES] La presente tesis se centra en la racionalización de la síntesis de zeolitas para su aplicación como catalizadores mediante la comprensión de la naturaleza de los sitios activos y sus microambientes, junto con su influencia en los mecanismos de las reacciones catalizadas. En la primera parte de la tesis, se han realizado esfuerzos para intentar lograr la ubicación regioselectiva de los sitios activos en el catalizador zeolítico y, más específicamente, en la ubicación controlada de sitios ácidos en la red cristalina de la zeolita. El desarrollo de una estrategia de síntesis adecuada junto con un indicador que pueda describir la distribución de aluminio en la red de la zeolita es importante para evaluar si se ha logrado el objetivo final. En esta parte, para evaluar la distribución de aluminio en la red de la zeolita MFI, se ha propuesto un indicador basado en los mecanismos monomoleculares y bimoleculares asociados a la reacción de craqueo catalítico de n-hexeno. En primer lugar, se sintetizaron varias muestras de ZSM-5, que según la literatura tienen diferentes distribuciones de aluminio. Estas muestras se caracterizaron por ser análogas en propiedades fisicoquímicas y, posteriormente, se analizaron en la reacción de craqueo de n-hexeno para justificar la utilidad del indicador propuesto en este trabajo. A partir de RMN MAS de 27Al se demostró que las ubicaciones de aluminio eran diferentes, lo que también se reflejó en el indicador propuesto en esta tesis, lo que justifica su aplicabilidad para evaluar distribuciones de aluminio. Posteriormente, este indicador se ha empleado para verificar la nueva metodología de síntesis de zeolitas que podría conducir a una distribución de aluminio diferente en sus estructuras cristalinas. En este sentido, se propone la síntesis de la zeolita ZSM-5 asistida por boro, considerando que el boro y el aluminio podrían tener un posicionamiento competitivo en la estructura MFI. Mediante cálculos de DFT, se ha estudiado si la celda unidad de MFI muestra diferente estabilidad cuando se introduce aluminio y/o boro en diferentes posiciones cristalográficas T. Se ha encontrado que la ubicación del boro está menos favorecida cuando se introduce en los canales de 10 miembros de la estructura MFI, mientras que el aluminio no muestra preferencia por el posicionamiento entre todos los sitios T. Se sintetizaron muestras de ZSM-5 con diferentes Si/Al y Si/B y se caracterizaron sus propiedades fisicoquímicas, así como la proporción relativa de estados emparejados y aislados de aluminio. La caracterización incluye el craqueo de n-hexeno, para el cual las muestras mostraron una preferencia diferente hacia las reacciones monomoleculares y bimoleculares. Finalmente, una vez demostrada la distinta distribución de aluminio en los materiales sintetizados, estos catalizadores se estudiaron en la reaccióde metanol a propeno (MTP) para mostrar la influencia de la distribución de aluminio en una reacción relevante a nivel industrial, donde el confinamiento espacial tiene un impacto importante. De hecho, las muestras con aluminio posicionadas preferentemente en un canal de 10 miembros favorecen reacciones de craqueo monomolecular frente a reacciones secundarias bimoleculares, como por ejemplo reacciones de oligomerización y de transferencia de hidrógeno, dando un mayor rendimiento a propeno y una menor cantidad de alcanos y compuestos aromáticos. La segunda parte de la tesis se centra en racionalizar la síntesis de zeolitas con cavidades para catalizar una reacción seleccionada "a priori". Más específicamente, la síntesis de zeolita se llevó a cabo utilizando agentes directores de estructura orgánicos (ADEO) que mimetizan el estado de transición (ET) o el intermedio relevante en la reacción objetivo. La producción de etilbenceno por transalquilación entre dietilbenceno y benceno se ha seleccionado como una reacción objetivo a catalizar. Se estableció el ET determinante de la reacción y se sintetizó un ADEO tipo diarildimetilfosfonio que mimetiza el estado de transición del mecanismo de la reacción de transalquilación entre benceno y dietilbenceno. Dicho ADEO permitió la cristalización de la zeolita de poro grande ITQ-27, cuyo comportamiento catalítico se estudió en la reacción de transalquilación entre benceno y dietilbenceno. La actividad catalítica de la zeolita ITQ-27 se mostró claramente superior al de otras zeolitas empleadas comercialmente, como USY, mordenita o Beta, todas ellas con propiedades fisicoquímicas similares a la ITQ-27. Finalmente, la reacción de metanol a olefinas (MTO) se eligió como otro sistema catalítico objetivo, donde los mecanismos de reacción son mucho más complicados que en el caso de la reacción de transalquilación entre benceno y dietilbenceno, pero, sin embargo, están bien establecidos en la literatura. Se sintetizaron varios ADEOs que mimetizan los intermedios y los estados de transición de la ruta “paring”, que produce más propeno y butenos, y que son posiblemente los productos más demandados. Dichos ADEOs mímicos permitieron la formación de varias zeolitas de poro pequeño basadas en cavidades, como las zeolitas CHA, RTH y AEI. Todas las zeolitas obtenidas se probaron en la reacción MTO para evaluar su actividad catalítica, obteniéndose una alta selectividad hacia distintas olefinas ligeras, cuya selectividad depende de la forma y tamaño de la cavidad de cada zeolita. La tendencia de cada estructura hacia ciertas distribuciones de productos se ha relacionado con el mecanismo de reacción, pudiendo establecer una correlación estructura-reactividad al combinar los resultados experimentales con cálculos teóricos.[CA] La present tesi es centra en la racionalització de la síntesi de zeolites per a la seva aplicació com a catalitzadors mitjançant la comprensió de la naturalesa dels centres actius i els seus microambientes, juntament amb la seva influència en els mecanismes de les reaccions catalitzades. A la primera part de la tesi, s'han realitzat esforços per intentar aconseguir la ubicació regioselectiva dels centres actius en el catalitzador zeolític i, més específicament, en la ubicació controlada de centres àcids en la xarxa cristal·lina de la zeolita. El desenvolupament d'una estratègia de síntesi adequada juntament amb un indicador que descriga la distribució d'alumini a la xarxa de la zeolita és important per avaluar si s'ha aconseguit l'objectiu final. En aquesta part, per avaluar la distribució d'alumini a la xarxa de la zeolita MFI, s'ha proposat un indicador basat en els mecanismes monomoleculares i bimoleculars associats a la reacció de craqueig catalític de n-hexé. En primer lloc, es van sintetitzar diverses mostres de ZSM-5, que segons la literatura tenen diferents distribucions d'alumini. Aquestes mostres es van caracteritzar per ser anàlogues en propietats fisicoquímiques i, posteriorment, es van analitzar en la reacció de craqueig de nhexéper justificar la utilitat de l'indicador proposat en aquest treball. A partir dels espectres de RMN MAS de 27Al es va demostrar que les ubicacions d'alumini eren diferents, el que també es va reflectir en l'indicador proposat en aquesta tesi, justificant la seva aplicabilitat per avaluar distintes distribucions d'alumini. Posteriorment, aquest indicador s'ha emprat per verificar la nova metodologia de síntesi de zeolites que podria conduir a una distribució d'alumini diferent al llarg de les seves estructures cristal·lines. En aquest sentit, s’ha proposat la síntesi de la zeolita ZSM-5 assistida per bor, considerant que el bor i l'alumini podrien tenir un posicionament competitiu en l'estructura MFI. Mitjançant càlculs de DFT, s'ha estudiat si la cel·la unitat de MFI mostra diferent estabilitat quan s’introdueix alumini i/o bor en diferents posicions cristal·logràfiques T. S'ha trobat que la ubicació dels àtoms de bor està menys afavorida als canals de 10 membres de la estructura MFI, mentre que l'alumini no mostra preferència pel posicionament entre tots els llocs T. Es van sintetitzar mostres de ZSM-5 amb diferents relacions de Si/Al i Si/B i es van caracteritzar les seves propietats fisicoquímiques, així com la proporció relativa d'estats aparellats i aïllats d'alumini. La caracterització inclou la reacció de craqueig de n-hexé, on les mostres van mostrar una preferència diferent cap a les reaccions monomoleculares i bimoleculars. Finalment, un cop demostrada la diferent distribució d'alumini en els materials sintetitzats, aquests catalitzadors es van estudiar a la reacció de metanol a propè (MTP) per mostrar la influència de la distribució d'alumini en una reacció rellevant a nivell industrial, on el confinament espacial té un impacte important. De fet, les mostres amb alumini posicionades preferentment en un canal de 10 membres afavoreixen reaccions de craqueig monomolecular enfront de reaccions secundàries bimoleculars, com ara reaccions d'oligomerització i de transferència d'hidrogen, donant un major rendiment a propè i una menor quantitat d'alcans i compostos aromàtics. La segona part de la tesi es centra en racionalitzar la síntesi de zeolites amb cavitats per catalitzar una reacció seleccionada "a priori". Més específicament, la síntesi de zeolita es va dur a terme utilitzant agents directors d'estructura orgànics (ADEO) que mimetitzen l'estat de transició (ET) o l'intermedi rellevant en la reacció objectiu. La producció de etilbenzèper transalquilació entre dietilbenzè i benzè s'ha seleccionat com una reacció objectiu a catalitzar. Es va establir l'ET determinant de la reacció i es va sintetitzar un ADEO tipus diarildimetilfosfoni que mimetitza eixe estat de transició. Eixe ADEO va permetre la cristal·lització de la zeolita de porus gran ITQ-27, i el seu comportament catalític es va estudiar en la reacció de transalquilación entre benzè i dietilbenzè. L'activitat catalítica de la zeolita ITQ-27 es va mostrar clarament superior a la d'altres zeolites emprades comercialment, com la USY, mordenita o Beta, totes elles amb propietats fisicoquímiques similars a la ITQ-27. Finalment, la reacció de metanol a olefines (MTO) es va triar com un altre sistema catalític objectiu, on els mecanismes de reacció són molt més complicats que en el cas de la reacció de transalquilació entre benzè i dietilbenzè, però que, al mateix temps, estan ben establerts en la literatura. Es van sintetitzar diversos ADEOs que mimetitzen alguns dels intermedis i dels estats de transició de la ruta "paring", que produeix més propè i butens, i que són possiblement els productes més demandats. Aquests ADEOs mímics van permetre la formació de diverses zeolites de porus petit basades en cavitats, com les zeolites CHA, RTH i AEI. Totes les zeolites obtingudes es van provar en la reacció MTO per avaluar la seva activitat catalítica, obtenint una alta selectivitat cap a diferents olefines lleugeres, on la selectivitat cap a cada olefina lleugera depèn de la forma i mida de la cavitat de cada zeolita. La tendència de cada estructura cap a certes distribucions de productes s'ha relacionat amb el mecanisme de reacció, i s´ha pogut establir una correlació estructura-reactivitat al combinar els resultats experimentals amb càlculs teòrics.Li, C. (2020). Rationalize the synthesis of zeolite catalysts by understanding reaction mechanism [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/147115TESI

Selective Introduction of Acid Sites in Different Confined Positions in ZSM-5 and Its Catalytic Implications

[EN] Controlling the location of acid sites in zeolites can have a great effect on catalysis. In this work we face the objective of directing the location of AI into the 10R channels of ZSM-5 by taking advantage of the structural preference of B to occupy certain positions at the channel intersections, as suggested by theoretical calculations. The synthesis of B-Al-ZSM-5 zeolites with variable Si/Al and Si/B ratios, followed by B removal in a postsynthesis treatment, produces ZSM-5 samples enriched in Al occupying positions at 10R channels. The location of the acid sites is determined on the basis of the product distribution of 1-hexene cracking as a test reaction. The higher selectivity to propene and lower C-4(=)/C-3(=) ratio in the samples synthesized with B and subsequently deboronated can be related to a larger concentration of acid sites in 10R channels, where monomolecular cracking occurs. Finally, several ZSM-5 samples have been tested in the methanol to propene reaction, and those synthesized through the B -assisted method show longer catalytic lifetime, higher propene yield, and lower yield of alkanes and aromatics.This work was supported by the European Union through ERC-AdG-2014-671093 (SynCatMatch) and the Spanish Government-MINECO through "Severo Ochoa" (SEV-2016-0683) and CTQ2015-70126-R. The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. Red Espanola de Supercomputacion (RES) and Centre de Calcul de la Universitat de Valencia are gratefully acknowledged for computational resources and technical support. C.L. acknowledges the China Scholarship Council (CSC) for a Ph.D. fellowshipLi, C.; Vidal Moya, JA.; Miguel, PJ.; Dedecek, J.; Boronat Zaragoza, M.; Corma Canós, A. (2018). Selective Introduction of Acid Sites in Different Confined Positions in ZSM-5 and Its Catalytic Implications. ACS Catalysis. 8(8):7688-7697. https://doi.org/10.1021/acscatal.8b02112S7688769788Brand, H. V., Curtiss, L. A., & Iton, L. E. (1993). Ab initio molecular orbital cluster studies of the zeolite ZSM-5. 1. Proton affinities. The Journal of Physical Chemistry, 97(49), 12773-12782. doi:10.1021/j100151a024Kassab, E., Seiti, K., & Allavena, M. (1988). Determination of structure and acidity scales in zeolite systems by ab initio and pseudopotential calculations. The Journal of Physical Chemistry, 92(23), 6705-6709. doi:10.1021/j100334a043Brändle, M., & Sauer, J. (1998). Acidity Differences between Inorganic Solids Induced by Their Framework Structure. A Combined Quantum Mechanics/Molecular Mechanics ab Initio Study on Zeolites. Journal of the American Chemical Society, 120(7), 1556-1570. doi:10.1021/ja9729037Jones, A. J., Carr, R. T., Zones, S. I., & Iglesia, E. (2014). Acid strength and solvation in catalysis by MFI zeolites and effects of the identity, concentration and location of framework heteroatoms. Journal of Catalysis, 312, 58-68. doi:10.1016/j.jcat.2014.01.007Jones, A. J., & Iglesia, E. (2015). The Strength of Brønsted Acid Sites in Microporous Aluminosilicates. ACS Catalysis, 5(10), 5741-5755. doi:10.1021/acscatal.5b01133Derouane, E. G. (1998). Zeolites as solid solvents1Paper presented at the International Symposium `Organic Chemistry and Catalysis’ on the occasion of the 65th birthday of Prof. H. van Bekkum, Delft, Netherlands, 2–3 October 1997.1. Journal of Molecular Catalysis A: Chemical, 134(1-3), 29-45. doi:10.1016/s1381-1169(98)00021-1Knott, B. C., Nimlos, C. T., Robichaud, D. J., Nimlos, M. R., Kim, S., & Gounder, R. (2017). Consideration of the Aluminum Distribution in Zeolites in Theoretical and Experimental Catalysis Research. ACS Catalysis, 8(2), 770-784. doi:10.1021/acscatal.7b03676Gounder, R., & Iglesia, E. (2013). The catalytic diversity of zeolites: confinement and solvation effects within voids of molecular dimensions. Chemical Communications, 49(34), 3491. doi:10.1039/c3cc40731dJones, A. J., & Iglesia, E. (2014). Kinetic, Spectroscopic, and Theoretical Assessment of Associative and Dissociative Methanol Dehydration Routes in Zeolites. Angewandte Chemie International Edition, 53(45), 12177-12181. doi:10.1002/anie.201406823Wang, S., & Iglesia, E. (2017). Catalytic diversity conferred by confinement of protons within porous aluminosilicates in Prins condensation reactions. Journal of Catalysis, 352, 415-435. doi:10.1016/j.jcat.2017.06.012Ghorbanpour, A., Rimer, J. D., & Grabow, L. C. (2014). Periodic, vdW-corrected density functional theory investigation of the effect of Al siting in H-ZSM-5 on chemisorption properties and site-specific acidity. Catalysis Communications, 52, 98-102. doi:10.1016/j.catcom.2014.04.005Mallikarjun Sharada, S., Zimmerman, P. M., Bell, A. T., & Head-Gordon, M. (2013). Insights into the Kinetics of Cracking and Dehydrogenation Reactions of Light Alkanes in H-MFI. The Journal of Physical Chemistry C, 117(24), 12600-12611. doi:10.1021/jp402506mJanda, A., & Bell, A. T. (2013). Effects of Si/Al Ratio on the Distribution of Framework Al and on the Rates of Alkane Monomolecular Cracking and Dehydrogenation in H-MFI. Journal of the American Chemical Society, 135(51), 19193-19207. doi:10.1021/ja4081937Olsbye, U., Svelle, S., Bjørgen, M., Beato, P., Janssens, T. V. W., Joensen, F., … Lillerud, K. P. (2012). Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity. Angewandte Chemie International Edition, 51(24), 5810-5831. doi:10.1002/anie.201103657Van Speybroeck, V., De Wispelaere, K., Van der Mynsbrugge, J., Vandichel, M., Hemelsoet, K., & Waroquier, M. (2014). First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev., 43(21), 7326-7357. doi:10.1039/c4cs00146jTian, P., Wei, Y., Ye, M., & Liu, Z. (2015). Methanol to Olefins (MTO): From Fundamentals to Commercialization. ACS Catalysis, 5(3), 1922-1938. doi:10.1021/acscatal.5b00007Svelle, S., Joensen, F., Nerlov, J., Olsbye, U., Lillerud, K.-P., Kolboe, S., & Bjørgen, M. (2006). Conversion of Methanol into Hydrocarbons over Zeolite H-ZSM-5:  Ethene Formation Is Mechanistically Separated from the Formation of Higher Alkenes. Journal of the American Chemical Society, 128(46), 14770-14771. doi:10.1021/ja065810aBJORGEN, M., SVELLE, S., JOENSEN, F., NERLOV, J., KOLBOE, S., BONINO, F., … OLSBYE, U. (2007). Conversion of methanol to hydrocarbons over zeolite H-ZSM-5: On the origin of the olefinic species. Journal of Catalysis, 249(2), 195-207. doi:10.1016/j.jcat.2007.04.006Wang, S., Chen, Y., Wei, Z., Qin, Z., Ma, H., Dong, M., … Wang, J. (2015). Polymethylbenzene or Alkene Cycle? Theoretical Study on Their Contribution to the Process of Methanol to Olefins over H-ZSM-5 Zeolite. The Journal of Physical Chemistry C, 119(51), 28482-28498. doi:10.1021/acs.jpcc.5b10299Teketel, S., Olsbye, U., Lillerud, K.-P., Beato, P., & Svelle, S. (2010). Selectivity control through fundamental mechanistic insight in the conversion of methanol to hydrocarbons over zeolites. Microporous and Mesoporous Materials, 136(1-3), 33-41. doi:10.1016/j.micromeso.2010.07.013Pinar, A. B., Márquez-Álvarez, C., Grande-Casas, M., & Pérez-Pariente, J. (2009). Template-controlled acidity and catalytic activity of ferrierite crystals. Journal of Catalysis, 263(2), 258-265. doi:10.1016/j.jcat.2009.02.017Román-Leshkov, Y., Moliner, M., & Davis, M. E. (2010). Impact of Controlling the Site Distribution of Al Atoms on Catalytic Properties in Ferrierite-Type Zeolites. The Journal of Physical Chemistry C, 115(4), 1096-1102. doi:10.1021/jp106247gDi Iorio, J. R., & Gounder, R. (2016). Controlling the Isolation and Pairing of Aluminum in Chabazite Zeolites Using Mixtures of Organic and Inorganic Structure-Directing Agents. Chemistry of Materials, 28(7), 2236-2247. doi:10.1021/acs.chemmater.6b00181Di Iorio, J. R., Nimlos, C. T., & Gounder, R. (2017). Introducing Catalytic Diversity into Single-Site Chabazite Zeolites of Fixed Composition via Synthetic Control of Active Site Proximity. ACS Catalysis, 7(10), 6663-6674. doi:10.1021/acscatal.7b01273Liu, M., Yokoi, T., Yoshioka, M., Imai, H., Kondo, J. N., & Tatsumi, T. (2014). Differences in Al distribution and acidic properties between RTH-type zeolites synthesized with OSDAs and without OSDAs. Physical Chemistry Chemical Physics, 16(9), 4155. doi:10.1039/c3cp54297aDedecek, J., Balgová, V., Pashkova, V., Klein, P., & Wichterlová, B. (2012). Synthesis of ZSM-5 Zeolites with Defined Distribution of Al Atoms in the Framework and Multinuclear MAS NMR Analysis of the Control of Al Distribution. Chemistry of Materials, 24(16), 3231-3239. doi:10.1021/cm301629aPashkova, V., Klein, P., Dedecek, J., Tokarová, V., & Wichterlová, B. (2015). Incorporation of Al at ZSM-5 hydrothermal synthesis. Tuning of Al pairs in the framework. Microporous and Mesoporous Materials, 202, 138-146. doi:10.1016/j.micromeso.2014.09.056Yokoi, T., Mochizuki, H., Namba, S., Kondo, J. N., & Tatsumi, T. (2015). Control of the Al Distribution in the Framework of ZSM-5 Zeolite and Its Evaluation by Solid-State NMR Technique and Catalytic Properties. The Journal of Physical Chemistry C, 119(27), 15303-15315. doi:10.1021/acs.jpcc.5b03289Liang, T., Chen, J., Qin, Z., Li, J., Wang, P., Wang, S., … Wang, J. (2016). Conversion of Methanol to Olefins over H-ZSM-5 Zeolite: Reaction Pathway Is Related to the Framework Aluminum Siting. ACS Catalysis, 6(11), 7311-7325. doi:10.1021/acscatal.6b01771Pashkova, V., Sklenak, S., Klein, P., Urbanova, M., & Dědeček, J. (2016). Location of Framework Al Atoms in the Channels of ZSM-5: Effect of the (Hydrothermal) Synthesis. Chemistry - A European Journal, 22(12), 3937-3941. doi:10.1002/chem.201503758Yokoi, T., Mochizuki, H., Biligetu, T., Wang, Y., & Tatsumi, T. (2017). Unique Al Distribution in the MFI Framework and Its Impact on Catalytic Properties. Chemistry Letters, 46(6), 798-800. doi:10.1246/cl.170156Sklenak, S., Dědeček, J., Li, C., Wichterlová, B., Gábová, V., Sierka, M., & Sauer, J. (2007). Aluminum Siting in Silicon-Rich Zeolite Frameworks: A Combined High-Resolution27Al NMR Spectroscopy and Quantum Mechanics / Molecular Mechanics Study of ZSM-5. Angewandte Chemie International Edition, 46(38), 7286-7289. doi:10.1002/anie.200702628Sklenak, S., Dědeček, J., Li, C., Wichterlová, B., Gábová, V., Sierka, M., & Sauer, J. (2009). Aluminium siting in the ZSM-5 framework by combination of high resolution 27Al NMR and DFT/MM calculations. Phys. Chem. Chem. Phys., 11(8), 1237-1247. doi:10.1039/b807755jDědeček, J., Sobalík, Z., & Wichterlová, B. (2012). Siting and Distribution of Framework Aluminium Atoms in Silicon-Rich Zeolites and Impact on Catalysis. Catalysis Reviews, 54(2), 135-223. doi:10.1080/01614940.2012.632662Wang, S., Wei, Z., Chen, Y., Qin, Z., Ma, H., Dong, M., … Wang, J. (2015). Methanol to Olefins over H-MCM-22 Zeolite: Theoretical Study on the Catalytic Roles of Various Pores. ACS Catalysis, 5(2), 1131-1144. doi:10.1021/cs501232rChen, J., Liang, T., Li, J., Wang, S., Qin, Z., Wang, P., … Wang, J. (2016). Regulation of Framework Aluminum Siting and Acid Distribution in H-MCM-22 by Boron Incorporation and Its Effect on the Catalytic Performance in Methanol to Hydrocarbons. ACS Catalysis, 6(4), 2299-2313. doi:10.1021/acscatal.5b02862Zhu, Q., Kondo, J. N., Yokoi, T., Setoyama, T., Yamaguchi, M., Takewaki, T., … Tatsumi, T. (2011). The influence of acidities of boron- and aluminium-containing MFI zeolites on co-reaction of methanol and ethene. Physical Chemistry Chemical Physics, 13(32), 14598. doi:10.1039/c1cp20338jYang, Y., Sun, C., Du, J., Yue, Y., Hua, W., Zhang, C., … Xu, H. (2012). The synthesis of endurable B–Al–ZSM-5 catalysts with tunable acidity for methanol to propylene reaction. Catalysis Communications, 24, 44-47. doi:10.1016/j.catcom.2012.03.013Hu, Z., Zhang, H., Wang, L., Zhang, H., Zhang, Y., Xu, H., … Tang, Y. (2014). Highly stable boron-modified hierarchical nanocrystalline ZSM-5 zeolite for the methanol to propylene reaction. Catal. Sci. Technol., 4(9), 2891-2895. doi:10.1039/c4cy00376dYaripour, F., Shariatinia, Z., Sahebdelfar, S., & Irandoukht, A. (2015). Effect of boron incorporation on the structure, products selectivities and lifetime of H-ZSM-5 nanocatalyst designed for application in methanol-to-olefins (MTO) reaction. Microporous and Mesoporous Materials, 203, 41-53. doi:10.1016/j.micromeso.2014.10.024Nachtigallová, D., Nachtigall, P., Sierka, M., & Sauer, J. (1999). Coordination and siting of Cu+ ions in ZSM-5: A combined quantum mechanics/interatomic potential function study. Physical Chemistry Chemical Physics, 1(8), 2019-2026. doi:10.1039/a900214fSchröder, K.-P., Sauer, J., Leslie, M., & A.Catlow, C. R. (1992). Siting of AI and bridging hydroxyl groups in ZSM-5: A computer simulation study. Zeolites, 12(1), 20-23. doi:10.1016/0144-2449(92)90004-9Schmidt, J. E., Fu, D., Deem, M. W., & Weckhuysen, B. M. (2016). Template–Framework Interactions in Tetraethylammonium‐Directed Zeolite Synthesis. Angewandte Chemie International Edition, 55(52), 16044-16048. doi:10.1002/anie.201609053Dědeček, J., Kaucký, D., Wichterlová, B., & Gonsiorová, O. (2002). Co2+ions as probes of Al distribution in the framework of zeolites. ZSM-5 study. Phys. Chem. Chem. Phys., 4(21), 5406-5413. doi:10.1039/b203966bBlay, V., Miguel, P. J., & Corma, A. (2017). Theta-1 zeolite catalyst for increasing the yield of propene when cracking olefins and its potential integration with an olefin metathesis unit. Catalysis Science & Technology, 7(24), 5847-5859. doi:10.1039/c7cy01502jSun, X., Mueller, S., Shi, H., Haller, G. L., Sanchez-Sanchez, M., van Veen, A. C., & Lercher, J. A. (2014). On the impact of co-feeding aromatics and olefins for the methanol-to-olefins reaction on HZSM-5. Journal of Catalysis, 314, 21-31. doi:10.1016/j.jcat.2014.03.013Teketel, S., Svelle, S., Lillerud, K.-P., & Olsbye, U. (2009). Shape-Selective Conversion of Methanol to Hydrocarbons Over 10-Ring Unidirectional-Channel Acidic H-ZSM-22. ChemCatChem, 1(1), 78-81. doi:10.1002/cctc.200900057Teketel, S., Skistad, W., Benard, S., Olsbye, U., Lillerud, K. P., Beato, P., & Svelle, S. (2011). Shape Selectivity in the Conversion of Methanol to Hydrocarbons: The Catalytic Performance of One-Dimensional 10-Ring Zeolites: ZSM-22, ZSM-23, ZSM-48, and EU-1. ACS Catalysis, 2(1), 26-37. doi:10.1021/cs200517

Design and Synthesis of the Active Site Environment in Zeolite Catalysts for Selectively Manipulating Mechanistic Pathways

[EN] By combining kinetics and theoretical calculations, we show here the benefits of going beyond the concept of static localized and defined active sites on solid catalysts, into a system that globally and dynamically considers the active site located in an environment that involves a scaffold structure particularly suited for a target reaction. We demonstrate that such a system is able to direct the reaction through a preferred mechanism when two of them are competing. This is illustrated here for an industrially relevant reaction, the diethylbenzene-benzene transalkylation. The zeolite catalyst (ITQ-27) optimizes location, density, and environment of acid sites to drive the reaction through the preselected and preferred diaryl-mediated mechanism, instead of the alkyl transfer pathway. This is achieved by minimizing the activation energy of the selected pathway through weak interactions, much in the way that it occurs in enzymatic catalysts. We show that ITQ-27 outperforms previously reported zeolites for the DEB-Bz transalkylation and, more specifically, industrially relevant zeolites such as faujasite, beta, and mordenite.This work was supported by the European Union through ERC-AdG-2014-671093 (SynCatMatch), Spanish Government through "Severo Ochoa" (SEV-2016-0683, MINECO), MAT2017-82288-C2-1-P (AEI/FEDER, UE) and RTI2018-10103-B-I00 (MCIU/AEI/FEDER, UE), and by Generalitat Valenciana through AICO/2019/060. The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. Red Espanola de Supercomputacion (RES) and Servei d'Informatica de la Universitat de Valencia (SIUV) are acknowledged for computational resources and technical support. P. F. and C. Li thank ITQ for their contract.Li, C.; Ferri-Vicedo, P.; Paris, C.; Moliner Marin, M.; Boronat Zaragoza, M.; Corma Canós, A. (2021). Design and Synthesis of the Active Site Environment in Zeolite Catalysts for Selectively Manipulating Mechanistic Pathways. Journal of the American Chemical Society. 143(28):10718-10726. https://doi.org/10.1021/jacs.1c0481810718107261432

The Limits of the Confinement Effect Associated to Cage Topology on the Control of the MTO Selectivity

This is the peer reviewed version of the following article: P. Ferri, C. Li, C. Paris, A. Rodríguez-Fernández, M. Moliner, M. Boronat, A. Corma, ChemCatChem 2021, 13, 1578, which has been published in final form at https://doi.org/10.1002/cctc.202001760. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The light olefin product distribution of the methanol-to-olefin (MTO) reaction catalyzed by acid zeolites and zeotypes depends on the nature of the entrapped hydrocarbon pool species that act as co-catalysts. The preferential stabilization by confinement effects of the cationic intermediates involved in the side-chain or paring pathways of the aromatics-based cycle of the MTO mechanism in small-pore cage-based zeolites is determined by the topology of the cavity, and can be quantitatively described through the E-int(7/5) parameter obtained from DFT calculations. In this work we extend the study of the E-int(7/5) parameter to a wide range of structures (ERI, LEV, AEI, CHA, DDR, AFX, RTH, ITE, SAV, UFI, RHO, KFI, and LTA) and discuss its applicability in small cages with steric constraints to host bulky intermediates, in zeolites with a tight fitting between the cavity and the hosted cations, and in large cages where confinement effects are lost in part and competitive processes occur.This work has been supported by the European Union through ERC-AdG-2014-671093 (SynCatMatch), Spanish Government through ''Severo Ochoa" (SEV-2016-0683, MINECO), MAT2017-82288-C2-1-P (AEI/FEDER, UE) and RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE), and by Generalitat Valenciana through AICO/2019/060. The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. Red Espanola de Supercomputacion (RES) and Servei d'Informatica de la Universitat de Valencia (SIUV) are acknowledged for computational resources and technical support. P.F. and C.L. thank ITQ for their contracts. A.R.F. acknowledges the Spanish Government-MINECO for a FPU scholarship (FPU2017/01521).Ferri-Vicedo, P.; Li, C.; Paris, C.; Rodríguez-Fernández, A.; Moliner Marin, M.; Boronat Zaragoza, M.; Corma Canós, A. (2021). The Limits of the Confinement Effect Associated to Cage Topology on the Control of the MTO Selectivity. ChemCatChem. 13(6):1578-1586. https://doi.org/10.1002/cctc.202001760S1578158613

Regioselective generation and reactivity control of subnanometric platinum clusters in zeolites for high-temperature catalysis

[EN] Subnanometric metal species (single atoms and clusters) have been demonstrated to be unique compared with their nanoparticulate counterparts. However, the poor stabilization of subnanometric metal species towards sintering at high temperature (>500 degrees C) under oxidative or reductive reaction conditions limits their catalytic application. Zeolites can serve as an ideal support to stabilize subnanometric metal catalysts, but it is challenging to localize subnanometric metal species on specific sites and modulate their reactivity. We have achieved a very high preference for localization of highly stable subnanometric Pt and PtSn clusters in the sinusoidal channels of purely siliceous MFI zeolite, as revealed by atomically resolved electron microscopy combining high-angle annular dark-field and integrated differential phase contrast imaging techniques. These catalysts show very high stability, selectivity and activity for the industrially important dehydrogenation of propane to form propylene. This stabilization strategy could be extended to other crystalline porous materials.This work has been supported by the European Union through the European Research Council (grant ERC-AdG-2014-671093, SynCatMatch) and the Spanish government through the Severo Ochoa Programme (SEV-2016-0683). L.L. thanks ITQ for providing a contract. The authors also thank the Microscopy Service of UPV for the TEM and STEM measurements. The XAS measurements were carried out in CLAESS beamline at the ALBA synchrotron. HR STEM measurements were performed at DME-UCA in Cadiz University with financial support from FEDER/MINECO (MAT2017-87579-R and MAT2016-81118-P). A relevant patent application (European patent application No. 19382024.8) has been presented. C.W.L. thanks CAPES (Science without Frontiers-Process no. 13191/13-6) for a predoctoral fellowship.Liu, L.; Lopez-Haro, M.; Lopes, CW.; Li, C.; Concepción Heydorn, P.; Simonelli, L.; Calvino, JJ.... (2019). Regioselective generation and reactivity control of subnanometric platinum clusters in zeolites for high-temperature catalysis. Nature Materials. 18(8):866-875. https://doi.org/10.1038/s41563-019-0412-6S86687518

Impact of Zeolite Framework Composition and Flexibility on Methanol-To-Olefins Selectivity: Confinement or Diffusion?

This is the peer reviewed version of the following article: P. Ferri, C. Li, R. Millán, J. Martínez-Triguero, M. Moliner, M. Boronat, A. Corma, Angew. Chem. Int. Ed. 2020, 59, 19708, which has been published in final form at https://doi.org/10.1002/anie.202007609. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The methanol-to-olefins reaction catalyzed by small-pore cage-based acid zeolites and zeotypes produces a mixture of short chain olefins, whose selectivity to ethene, propene and butene varies with the cavity architecture and with the framework composition. The product distribution of aluminosilicates and silicoaluminophosphates with the CHA and AEI structures (H-SSZ-13, H-SAPO-34, H-SSZ-39 and H-SAPO-18) has been experimentally determined, and the impact of acidity and framework flexibility on the stability of the key cationic intermediates involved in the mechanism and on the diffusion of the olefin products through the8rwindows of the catalysts has been evaluated by means of periodic DFT calculations and ab initio molecular dynamics simulations. The preferential stabilization by confinement of fully methylated hydrocarbon pool intermediates favoring the paring pathway is the main factor controlling the final olefin product distribution.This work has been supported by the European Union through ERC-AdG-2014-671093 (SynCatMatch), Spanish Government through "Severo Ochoa" (SEV-2016-0683, MINECO), MAT2017-82288-C2-1-P (AEI/FEDER, UE) and RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE), and by Generalitat Valenciana through AICO/2019/060. The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. Red Espanola de Supercomputacion (RES) and Servei d'Informatica de la Universitat de Valencia (SIUV) are acknowledged for computational resources and technical support. P.F. and R.M. thank ITQ for their contracts. C.L. acknowledges China Scholarship Council (CSC) for a Ph.D fellowship.Ferri-Vicedo, P.; Li, C.; Millán-Cabrera, R.; Martínez-Triguero, J.; Moliner Marin, M.; Boronat Zaragoza, M.; Corma Canós, A. (2020). Impact of Zeolite Framework Composition and Flexibility on Methanol-To-Olefins Selectivity: Confinement or Diffusion?. Angewandte Chemie International Edition. 59(44):19708-19715. https://doi.org/10.1002/anie.202007609S19708197155944Olah, G. A. (2005). Beyond Oil and Gas: The Methanol Economy. Angewandte Chemie International Edition, 44(18), 2636-2639. doi:10.1002/anie.200462121Olah, G. A. (2005). Jenseits von Öl und Gas: die Methanolwirtschaft. Angewandte Chemie, 117(18), 2692-2696. doi:10.1002/ange.200462121Tian, P., Wei, Y., Ye, M., & Liu, Z. (2015). Methanol to Olefins (MTO): From Fundamentals to Commercialization. ACS Catalysis, 5(3), 1922-1938. doi:10.1021/acscatal.5b00007Haw, J. F., Song, W., Marcus, D. M., & Nicholas, J. B. (2003). The Mechanism of Methanol to Hydrocarbon Catalysis. Accounts of Chemical Research, 36(5), 317-326. doi:10.1021/ar020006oOlsbye, U., Svelle, S., Bjørgen, M., Beato, P., Janssens, T. V. W., Joensen, F., … Lillerud, K. P. (2012). Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity. Angewandte Chemie International Edition, 51(24), 5810-5831. doi:10.1002/anie.201103657Olsbye, U., Svelle, S., Bjørgen, M., Beato, P., Janssens, T. V. W., Joensen, F., … Lillerud, K. P. (2012). Umwandlung von Methanol in Kohlenwasserstoffe: Wie Zeolith-Hohlräume und Porengröße die Produktselektivität bestimmen. Angewandte Chemie, 124(24), 5910-5933. doi:10.1002/ange.201103657Van Speybroeck, V., De Wispelaere, K., Van der Mynsbrugge, J., Vandichel, M., Hemelsoet, K., & Waroquier, M. (2014). First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev., 43(21), 7326-7357. doi:10.1039/c4cs00146jYarulina, I., Chowdhury, A. D., Meirer, F., Weckhuysen, B. M., & Gascon, J. (2018). Recent trends and fundamental insights in the methanol-to-hydrocarbons process. Nature Catalysis, 1(6), 398-411. doi:10.1038/s41929-018-0078-5Moliner, M., Martínez, C., & Corma, A. (2013). Synthesis Strategies for Preparing Useful Small Pore Zeolites and Zeotypes for Gas Separations and Catalysis. Chemistry of Materials, 26(1), 246-258. doi:10.1021/cm4015095McCann, D. M., Lesthaeghe, D., Kletnieks, P. W., Guenther, D. R., Hayman, M. J., Van Speybroeck, V., … Haw, J. F. (2008). A Complete Catalytic Cycle for Supramolecular Methanol‐to‐Olefins Conversion by Linking Theory with Experiment. Angewandte Chemie International Edition, 47(28), 5179-5182. doi:10.1002/anie.200705453McCann, D. M., Lesthaeghe, D., Kletnieks, P. W., Guenther, D. R., Hayman, M. J., Van Speybroeck, V., … Haw, J. F. (2008). A Complete Catalytic Cycle for Supramolecular Methanol‐to‐Olefins Conversion by Linking Theory with Experiment. Angewandte Chemie, 120(28), 5257-5260. doi:10.1002/ange.200705453Wang, C.-M., Wang, Y.-D., Xie, Z.-K., & Liu, Z.-P. (2009). Methanol to Olefin Conversion on HSAPO-34 Zeolite from Periodic Density Functional Theory Calculations: A Complete Cycle of Side Chain Hydrocarbon Pool Mechanism. The Journal of Physical Chemistry C, 113(11), 4584-4591. doi:10.1021/jp810350xIlias, S., & Bhan, A. (2012). Mechanism of the Catalytic Conversion of Methanol to Hydrocarbons. ACS Catalysis, 3(1), 18-31. doi:10.1021/cs3006583De Wispelaere, K., Hemelsoet, K., Waroquier, M., & Van Speybroeck, V. (2013). Complete low-barrier side-chain route for olefin formation during methanol conversion in H-SAPO-34. Journal of Catalysis, 305, 76-80. doi:10.1016/j.jcat.2013.04.015Hemelsoet, K., Van der Mynsbrugge, J., De Wispelaere, K., Waroquier, M., & Van Speybroeck, V. (2013). Unraveling the Reaction Mechanisms Governing Methanol-to-Olefins Catalysis by Theory and Experiment. ChemPhysChem, 14(8), 1526-1545. doi:10.1002/cphc.201201023Li, J., Wei, Y., Chen, J., Tian, P., Su, X., Xu, S., … Liu, Z. (2011). Observation of Heptamethylbenzenium Cation over SAPO-Type Molecular Sieve DNL-6 under Real MTO Conversion Conditions. Journal of the American Chemical Society, 134(2), 836-839. doi:10.1021/ja209950xXu, S., Zheng, A., Wei, Y., Chen, J., Li, J., Chu, Y., … Liu, Z. (2013). Direct Observation of Cyclic Carbenium Ions and Their Role in the Catalytic Cycle of the Methanol-to-Olefin Reaction over Chabazite Zeolites. Angewandte Chemie International Edition, 52(44), 11564-11568. doi:10.1002/anie.201303586Xu, S., Zheng, A., Wei, Y., Chen, J., Li, J., Chu, Y., … Liu, Z. (2013). Direct Observation of Cyclic Carbenium Ions and Their Role in the Catalytic Cycle of the Methanol-to-Olefin Reaction over Chabazite Zeolites. Angewandte Chemie, 125(44), 11778-11782. doi:10.1002/ange.201303586Li, J., Wei, Y., Chen, J., Xu, S., Tian, P., Yang, X., … Liu, Z. (2014). Cavity Controls the Selectivity: Insights of Confinement Effects on MTO Reaction. ACS Catalysis, 5(2), 661-665. doi:10.1021/cs501669kZhang, W., Chen, J., Xu, S., Chu, Y., Wei, Y., Zhi, Y., … Liu, Z. (2018). Methanol to Olefins Reaction over Cavity-type Zeolite: Cavity Controls the Critical Intermediates and Product Selectivity. ACS Catalysis, 8(12), 10950-10963. doi:10.1021/acscatal.8b02164Song, W., Fu, H., & Haw, J. F. (2001). Supramolecular Origins of Product Selectivity for Methanol-to-Olefin Catalysis on HSAPO-34. Journal of the American Chemical Society, 123(20), 4749-4754. doi:10.1021/ja0041167Svelle, S., Olsbye, U., Joensen, F., & Bjørgen, M. (2007). Conversion of Methanol to Alkenes over Medium- and Large-Pore Acidic Zeolites:  Steric Manipulation of the Reaction Intermediates Governs the Ethene/Propene Product Selectivity. The Journal of Physical Chemistry C, 111(49), 17981-17984. doi:10.1021/jp077331jHwang, A., Johnson, B. A., & Bhan, A. (2019). Mechanistic study of methylbenzene dealkylation in methanol-to-olefins catalysis on HSAPO-34. Journal of Catalysis, 369, 86-94. doi:10.1016/j.jcat.2018.10.022Bhawe, Y., Moliner-Marin, M., Lunn, J. D., Liu, Y., Malek, A., & Davis, M. (2012). Effect of Cage Size on the Selective Conversion of Methanol to Light Olefins. ACS Catalysis, 2(12), 2490-2495. doi:10.1021/cs300558xKang, J. H., Walter, R., Xie, D., Davis, T., Chen, C.-Y., Davis, M. E., & Zones, S. I. (2018). Further Studies on How the Nature of Zeolite Cavities That Are Bounded by Small Pores Influences the Conversion of Methanol to Light Olefins. ChemPhysChem, 19(4), 412-419. doi:10.1002/cphc.201701197Kang, J. H., Alshafei, F. H., Zones, S. I., & Davis, M. E. (2019). Cage-Defining Ring: A Molecular Sieve Structural Indicator for Light Olefin Product Distribution from the Methanol-to-Olefins Reaction. ACS Catalysis, 9(7), 6012-6019. doi:10.1021/acscatal.9b00746Li, C., Paris, C., Martínez-Triguero, J., Boronat, M., Moliner, M., & Corma, A. (2018). Synthesis of reaction‐adapted zeolites as methanol-to-olefins catalysts with mimics of reaction intermediates as organic structure‐directing agents. Nature Catalysis, 1(7), 547-554. doi:10.1038/s41929-018-0104-7Ferri, P., Li, C., Paris, C., Vidal-Moya, A., Moliner, M., Boronat, M., & Corma, A. (2019). Chemical and Structural Parameter Connecting Cavity Architecture, Confined Hydrocarbon Pool Species, and MTO Product Selectivity in Small-Pore Cage-Based Zeolites. ACS Catalysis, 9(12), 11542-11551. doi:10.1021/acscatal.9b04588Chen, J., Li, J., Yuan, C., Xu, S., Wei, Y., Wang, Q., … Liu, Z. (2014). Elucidating the olefin formation mechanism in the methanol to olefin reaction over AlPO-18 and SAPO-18. Catalysis Science & Technology, 4(9), 3268. doi:10.1039/c4cy00551aDusselier, M., Deimund, M. A., Schmidt, J. E., & Davis, M. E. (2015). Methanol-to-Olefins Catalysis with Hydrothermally Treated Zeolite SSZ-39. ACS Catalysis, 5(10), 6078-6085. doi:10.1021/acscatal.5b01577Martín, N., Li, Z., Martínez-Triguero, J., Yu, J., Moliner, M., & Corma, A. (2016). Nanocrystalline SSZ-39 zeolite as an efficient catalyst for the methanol-to-olefin (MTO) process. Chemical Communications, 52(36), 6072-6075. doi:10.1039/c5cc09719cMartínez-Franco, R., Li, Z., Martínez-Triguero, J., Moliner, M., & Corma, A. (2016). Improving the catalytic performance of SAPO-18 for the methanol-to-olefins (MTO) reaction by controlling the Si distribution and crystal size. Catalysis Science & Technology, 6(8), 2796-2806. doi:10.1039/c5cy02298cBleken, F., Bjørgen, M., Palumbo, L., Bordiga, S., Svelle, S., Lillerud, K.-P., & Olsbye, U. (2009). The Effect of Acid Strength on the Conversion of Methanol to Olefins Over Acidic Microporous Catalysts with the CHA Topology. Topics in Catalysis, 52(3), 218-228. doi:10.1007/s11244-008-9158-0Wang, C.-M., Wang, Y.-D., Du, Y.-J., Yang, G., & Xie, Z.-K. (2015). Similarities and differences between aromatic-based and olefin-based cycles in H-SAPO-34 and H-SSZ-13 for methanol-to-olefins conversion: insights from energetic span model. Catalysis Science & Technology, 5(9), 4354-4364. doi:10.1039/c5cy00483gGallego, E. M., Li, C., Paris, C., Martín, N., Martínez-Triguero, J., Boronat, M., … Corma, A. (2018). Making Nanosized CHA Zeolites with Controlled Al Distribution for Optimizing Methanol-to-Olefin Performance. Chemistry - A European Journal, 24(55), 14631-14635. doi:10.1002/chem.201803637Chen, D., Moljord, K., & Holmen, A. (2012). A methanol to olefins review: Diffusion, coke formation and deactivation on SAPO type catalysts. Microporous and Mesoporous Materials, 164, 239-250. doi:10.1016/j.micromeso.2012.06.046Wang, C., Li, B., Wang, Y., & Xie, Z. (2013). Insight into the topology effect on the diffusion of ethene and propene in zeolites: A molecular dynamics simulation study. Journal of Energy Chemistry, 22(6), 914-918. doi:10.1016/s2095-4956(14)60272-2Ghysels, A., Moors, S. L. C., Hemelsoet, K., De Wispelaere, K., Waroquier, M., Sastre, G., & Van Speybroeck, V. (2015). Shape-Selective Diffusion of Olefins in 8-Ring Solid Acid Microporous Zeolites. The Journal of Physical Chemistry C, 119(41), 23721-23734. doi:10.1021/acs.jpcc.5b06010Cnudde, P., Demuynck, R., Vandenbrande, S., Waroquier, M., Sastre, G., & Speybroeck, V. V. (2020). Light Olefin Diffusion during the MTO Process on H-SAPO-34: A Complex Interplay of Molecular Factors. Journal of the American Chemical Society, 142(13), 6007-6017. doi:10.1021/jacs.9b10249“Structure Commission of the International Zeolite Association (IZA-SC) Database of Zeolite structures ” can be found underhttp://www.iza-structure.org/databases/ n.d.Olson, D. H., Camblor, M. A., Villaescusa, L. A., & Kuehl, G. H. (2004). Light hydrocarbon sorption properties of pure silica Si-CHA and ITQ-3 and high silica ZSM-58. Microporous and Mesoporous Materials, 67(1), 27-33. doi:10.1016/j.micromeso.2003.09.025Ruthven, D. M., & Reyes, S. C. (2007). Adsorptive separation of light olefins from paraffins. Microporous and Mesoporous Materials, 104(1-3), 59-66. doi:10.1016/j.micromeso.2007.01.005Hedin, N., DeMartin, G. J., Roth, W. J., Strohmaier, K. G., & Reyes, S. C. (2008). PFG NMR self-diffusion of small hydrocarbons in high silica DDR, CHA and LTA structures. Microporous and Mesoporous Materials, 109(1-3), 327-334. doi:10.1016/j.micromeso.2007.05.007Li, Z., Martínez-Triguero, J., Concepción, P., Yu, J., & Corma, A. (2013). Methanol to olefins: activity and stability of nanosized SAPO-34 molecular sieves and control of selectivity by silicon distribution. Physical Chemistry Chemical Physics, 15(35), 14670. doi:10.1039/c3cp52247

Chemical and Structural Parameter Connecting Cavity Architecture, Confined Hydrocarbon Pool Species, and MTO Product Selectivity in Small-Pore Cage-Based Zeolites

"This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acscatal.9b04588"[EN] The catalysts used in the methanol-to-olefins (MTO) reaction are considered dual systems comprising an inorganic zeolite framework and organic compounds hosted inside that act as cocatalysts. The influence of zeolite cavity architecture on the preferential stabilization of cationic intermediates involved in the paring and side-chain routes of the hydrocarbon pool mechanism is analyzed by means of density functional theory (DFT) calculations, catalyst testing, and C-13 NMR spectroscopy for some small-pore cage-based zeolites. A correlation between the degree of methylation of the entrapped methylbenzenium (MB+) cations and the selectivity to ethene and propene is found experimentally and explained in terms of the electronic distribution of the first intermediate of the paring route. A deep understanding of the reaction mechanism and of the specific host guest interactions taking place inside zeolite catalysts allows establishing a quantitative parameter that is indicative for the contribution of the paring route and therefore the C-3(=)/C-2(=) ratio in the MTO reaction.This work has been supported by the European Union through ERC-AdG-2014-671093 (SynCatMatch), Spanish Government through "Severo Ochoa" (SEV-2016-0683, MINECO), MAT2017-82288-C2-1-P (AEI/FEDER, UE), and RTI2018-101033-B-100 (MCIU/AEI/FEDER, UE), and by the Fundacion Ramon Areces through a research contract (CIVP18A3908). The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. Red Espanola de Supercomputacion (RES) and Servei d'Informatica de la Universitat de Valencia are acknowledged for computational resources and technical support. C.L. acknowledges the China Scholarship Council (CSC) for a Ph.D. fellowship. P.F. thanks ITQ for acontract. The authors thank Prof. Fernando Rey and Dr. Joaquin Martinez for helpful discussions.Ferri-Vicedo, P.; Li, C.; Paris, C.; Vidal Moya, JA.; Moliner Marin, M.; Boronat Zaragoza, M.; Corma Canós, A. (2019). Chemical and Structural Parameter Connecting Cavity Architecture, Confined Hydrocarbon Pool Species, and MTO Product Selectivity in Small-Pore Cage-Based Zeolites. ACS Catalysis. 9(12):11542-11551. https://doi.org/10.1021/acscatal.9b04588S115421155191

Station-network cooperative planning method of urban integrated energy system based on energy flow model

Coordinated siting and sizing for energy stations and supply networks in urban integrated energy system (UIES) is significant for economic improvement and carbon emissions reduction. A station-network cooperative planning method of UIES based on energy flow model is proposed. First, an operation model of heat network based on energy flow theory is proposed, which solves the problem that the temperature mixing equation in the traditional operation model cannot be applied to heat network planning. On this basis, a bi-level model for station-network cooperative planning of UIES is constructed, in which the upper level optimizes the siting and sizing of the energy station and the topology of the supply network, and the lower level optimizes the operation of the UIES and feeds back the operation cost of the UIES to the upper level. Finally, a solution method of cooperative planning based on the Karush-Kuhn-Tucher condition is proposed, to transform the bi-level nonlinear optimization model into a single-level linear optimization model for efficient solution. Case studies on the 55-node and 77-road urban topology show that the proposed method can perform an effective planning on energy supply network topology and rationally configure the capacity of various devices in the energy station

Low-temperature hydroformylation of ethylene by phosphorous stabilized Rh sites in a one-pot synthesized Rh-(O)-P-MFI zeolite

Zeolites containing Rh single sites stabilized by phosphorous were prepared through a one-pot synthesis method and are shown to have superior activity and selectivity for ethylene hydroformylation at low temperature (50 °C). Catalytic activity is ascribed to confined RhO clusters in the zeolite which evolve under reaction conditions into single Rh sites. These Rh sites are effectively stabilized in a Rh-(O)-P structure by using tetraethylphosphonium hydroxide as a template, which generates in situ phosphate species after H activation. In contrast to RhO, confined Rh clusters appear less active in propanal production and ultimately transform into Rh(I)(CO) under similar reaction conditions. As a result, we show that it is possible to reduce the temperature of ethylene hydroformylation with a solid catalyst down to 50 °C, with good activity and high selectivity, by controlling the electronic and morphological properties of Rh species and the reaction conditions.P.C. thanks the Ministerio de Ciencia, Innovación y Universidades, grant number PID2021-1262350B-C31, and Generalitat Valenciana (GVA), grant number CIAICO/2021/2138. P.C. and D.G. thank the Advanced Materials Programme supported by MCIN with funding from European Union Next Generation EU (PRTR-C17.11) (TED2021-130756B-C32) and by Generalitad Valenciana (ref MFA/2022/016). M.Z. acknowledges the China Scholarship Council (CSC) for Ph.D. fellowship (CSC NO. 202006440003). XAS experiments were performed at the ALBA Synchrotron (BL-22 CLÆSS) with the collaboration of ALBA staff. XANES of Rh-(O)-P-MFI samples were analyzed at the Advanced Photon Source, an Office of Science User Facility operated by Argonne National Laboratory for the U.S. Department of Energy (DOE) Office of Science. The U.S. DOE supported it under Contract No. DE-AC02-06CH11357, and the Canadian Light Source and its funding partners. HR-HAADF-STEM measurements were performed at DME-UCA at Cadiz University. M.L.H. and J.J.C. thank the financial support from the Department of Economy, Knowledge, Business and the University of the Regional Government of Andalusia, Project reference FEDER-UCA18-107139

Silicon photonic chiplet-based CPU/GPU system design

Modern GPU/CPU systems integrate hundreds of cores on a single die, and future scaling envisions even more cores being incorporated. However, this growth is constrained by the limited number of transistors per die. To address this challenge, chiplet technology has emerged as a promising approach due to its higher integration density, improved flexibility, and reduced cost. Nevertheless, existing chiplet interconnection technologies suffer from limitations in terms of bandwidth, latency, and energy efficiency. In contrast, optical interconnects offer significant advantages, including low latency, ultra-high bandwidth, and good energy efficiency, making them an ideal choice for high-performance chiplet-based systems. However, previously proposed optical networks lack scalability and are not directly applicable to existing chiplet-based systems. Moreover, they ignore the communication characteristics specific to CPU/GPU systems. To address these issues comprehensively, we establish a power model and an optical device cost model for inter-chiplet optical interconnect. Additionally, we conduct a quantitative analysis of the traffic characteristics within chiplet-based CPU and GPU systems. Based on these findings, we introduce a photonic cache coherence network (PCCN) for chiplet-based manycore processors, which accelerates cache coherence transactions and alleviates cache coherence overhead. We propose a novel region-based optical network (RONet) with a tuning-free mechanism for chiplet-based GPU, which significantly enhances system performance and energy efficiency. Considering the limitation of RONet, we further optimize our design and propose a group-based optical network (GROOT), which is more scalable and resolves the NUMA issue in RONet.</p