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dc.contributor.authorKalantzopoulos, Georgios N.
dc.contributor.authorLundvall, Fredrik
dc.contributor.authorThorshaug, Knut
dc.contributor.authorLind, Anna Maria
dc.contributor.authorVajeeston, Ponniah
dc.contributor.authorDovgaliuk, Iurii
dc.contributor.authorArstad, Bjørnar
dc.contributor.authorWragg, David
dc.contributor.authorFjellvåg, Helmer
dc.identifier.citationChemistry of Materials. 2020, 32 (4), 1495-1505.en_US
dc.description.abstractSilicoaluminophosphates (SAPOs) are a special class of zeolites that, due to their acidic and shape-selective properties, play a major role in ion exchange and separation processes and in crude oil cracking. SAPO-37 has the faujasite (FAU) topology same as zeolites X and Y, which are involved in more than 40% of the total crude oil conversion worldwide. A critical parameter that promotes detrimental structural transformations in SAPOs during real-life applications is the presence of humidity. In this study, we employ a multidisciplinary approach combining in situ synchrotron radiation powder X-ray diffraction (SR-PXRD), water adsorption, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and density functional theory (DFT) calculations to describe the mechanism and reveal the reasons why SAPO-37 collapses upon contact with humidity below 345 K. SR-PXRD revealed that the sodalite (SOD) cages (subunits of the FAU structure) have the strongest affinity to water during hydration below 345 K. Furthermore, below 345 K, the faujasite framework takes up an order of magnitude more water molecules than at temperatures above 345 K. DRIFTS confirmed the presence of Si−OH and P−OH surface structural defects that act as hydration centers, accelerating the loss of a long-range order. Finally, DFT calculations showed that the enthalpy of water adsorption in the sodalite cage and the faujasite supercage is −212 and −13 kJ/mol, respectively. The results presented in this work are highly topical for understanding the effect of water on the frameworks of the SAPO microporous catalysts family. The notorious instability of SAPO-37 is the result of the accumulative contribution of topological, physical, and chemical effects, leading to an array of rapidly evolving cascading effects. Our work shows how advancements in SR-PXRD methodology and hardware give new insight into highly dynamic features previously difficult to observe. In addition, this work introduces the conceptual insight that nonhomogeneous sorption of molecular species will induce dynamic features with dramatic consequences at both molecular and atomic levels. This is a highly impactful factor opening research paths for further work within catalysis, porous material design and chemistry, and sorption reactions and processes.en_US
dc.publisherACS Publishingen_US
dc.rightsNavngivelse 4.0 Internasjonal*
dc.subjectMicroporous Materialen_US
dc.subjectSeparation processesen_US
dc.subjectCrude oil crackingen_US
dc.titleFactors Determining Microporous Material Stability in Water: The Curious Case of SAPO-37en_US
dc.typePeer revieweden_US
dc.typeJournal articleen_US
dc.rights.holder© 2020 American Chemical Societyen_US
dc.source.journalChemistry of Materialsen_US
dc.relation.projectNorges forskningsråd: 233848en_US
dc.relation.projectNorges forskningsråd: 208896en_US
dc.relation.projectInterreg: 190980en_US
dc.relation.projectNotur/NorStore: NN2875Ken_US
dc.relation.projectNotur/NorStore: NS2875Ken_US
cristin.unitnameMaterialer og nanoteknologi

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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal