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dc.contributor.authorZichun, Wang
dc.contributor.authorYijiao, Jiang
dc.contributor.authorXianfeng, Yi
dc.contributor.authorCuifeng, Zhou
dc.contributor.authorAditya, Rawal
dc.contributor.authorJames, Hook
dc.contributor.authorZongwen, Liu
dc.contributor.authorFeng, Deng
dc.contributor.authorAnmin, Zheng
dc.contributor.authorMichael, Hunger
dc.contributor.authorAlfons, Baiker
dc.contributor.authorJun, Huang
dc.date.accessioned2021-01-22T04:34:15Z
dc.date.available2021-01-22T04:34:15Z
dc.date.issued2019en_AU
dc.identifier.urihttps://hdl.handle.net/2123/24364
dc.description.abstractPentacoordinated Al (AlV) species in silica-alumina are promising to promote the formation of acid sites or act as surface defects for tailoring single-atom catalysts. However, pentahedral coordination (AlV) is rarely observed in conventionally prepared silica-alumina. Here, we show that high population and dispersion of AlV species on the surface of amorphous silica-alumina (ASA) can be achieved by means of flame spray pyrolysis. High resolution TEM/EDX, high magnetic-field NMR and DFT calculations are employed to characterize the structure of as-prepared ASAs. Solid-state 27Al multi-quantum MAS NMR experiments show that most of the AlV species are formed independently from the alumina phase and are accessible for guest molecules on the surface. Upon water adsorption, these AlV species are transformed to AlVI species, structurally similar to surface AlIV species, as confirmed by DFT calculations. The outstanding catalytic activity of as-synthesized ASA is demonstrated using the in situ H/D exchange reaction with deuterated benzene as an example. The AlV-rich ASA provides a much lower activation energy (∼30 kJ/mol) than that reported for zeolite H-ZSM-5 (∼60 kJ/mol). The superior catalytic performance is attributed to the high AlV content promoting the surface active sites in ASA. The knowledge gained on the synthesis of AlV-rich ASAs and the nature of aluminum coordination in these materials could pave the way to more efficient silica-alumina based catalysts.en_AU
dc.language.isoenen_AU
dc.publisherELSEVIERen_AU
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivatives 4.0en_AU
dc.titleHigh population and dispersion of pentacoordinated AlV species on the surface of flame-made amorphous silicaaluminaen_AU
dc.typeArticleen_AU
dc.subject.asrc03 Chemical Sciencesen_AU
dc.subject.asrc0904 Chemical Engineeringen_AU
dc.identifier.doi10.1016/j.scib.2019.04.002
dc.relation.arcDP150103842
usyd.facultySeS faculties schools::Faculty of Engineeringen_AU
workflow.metadata.onlyNoen_AU


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