@article{849df24f15214344a04d01e5a1439561,
title = "Creating Br{\o}nsted acidity at the SiO2-Nb2O5 interface",
abstract = "Catalytically active acid sites associated with the silica-niobia interface were probed with a series of overcoated SiO2 on Nb2O5 (SiO2/Nb2O5) mixed oxide materials prepared by deposition of tetraethyl orthosilicate onto niobic acid (Nb2O5·nH2O) or calcined niobia (Nb2O5). NH3 TPD and pyridine DRIFTS studies indicated that the speciation of acid sites in the materials evolved as a function of SiO2 loading, impacting the quantity and stability of Br{\o}nsted sites. Catalyst activity was highly dependent on SiO2 loading in the liquid phase hydroalkoxylation of dihydropyran with n-octanol. At SiO2 surface densities corresponding to approximately 1 Si per 2 surface Nb, the activity of these catalysts passed through a maximum approximately 20 times higher than the activity of calcined Nb2O5. Apparent reaction barriers measured over the most active SiO2/Nb2O5 catalysts were 10 kJ/mol lower than those measured over niobic acid, suggesting that the OH features unique to the SiO2-Nb2O5 interface were slightly more reactive than those on niobic acid.",
keywords = "Br{\o}nsted acids, Hydroalkoxylation, Mixed oxides, Niobic acid, Overcoated materials, Tetrahydropyranylation",
author = "Wolek, {Andrew T.Y.} and Ardagh, {M. Alexander} and Pham, {Hien N.} and Selim Alayoglu and Datye, {Abhaya K.} and Notestein, {Justin M.}",
note = "Funding Information: Metal analysis was performed at the Northwestern University Quantitative Bio-element Imaging Center. This work made use of the EPIC facility of Northwestern University{\textquoteright}s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. This work made use of the Jerome B.Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1720139) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHYNE) Resource (NSF ECCS-1542205.) The REACT Core facility acknowledges funding from the Department of Energy (DE-FG02-03ER15457) used for the purchase of the Altamira AMI-200 and the Nicolet 6700 FT-IR. Funding Information: A.T.Y.W. would like to thank Vincent Cheng for assistance with running tetrahydropyranylation reactions. A.T.Y.W thanks Mihir Bhagat for assistance with method development for GC-MS analyses. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DOE DE-FG02-03ER15457 for support of M.A.A. and S.A. and the National Science Foundation under Cooperative Agreement No. EEC-1647722 for support of A.T.Y.W. Metal analysis was performed at the Northwestern University Quantitative Bio-element Imaging Center. This work made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. This work made use of the Jerome B.Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1720139) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHYNE) Resource (NSF ECCS-1542205.) The REACT Core facility acknowledges funding from the Department of Energy (DE-FG02-03ER15457) used for the purchase of the Altamira AMI-200 and the Nicolet 6700 FT-IR. Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DOE DE-FG02-03-ER154757 for support of M.A.A., S.A. and the National Science Foundation under Cooperative Agreement No. EEC-1647722 for support of A.T.Y.W. Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DOE DE-FG02-03ER15457 for support of M.A.A. and S.A. and the National Science Foundation under Cooperative Agreement No. EEC-1647722 for support of A.T.Y.W. Publisher Copyright: {\textcopyright} 2020 Elsevier Inc.",
year = "2021",
month = feb,
doi = "10.1016/j.jcat.2020.10.027",
language = "English (US)",
volume = "394",
pages = "387--396",
journal = "Journal of Catalysis",
issn = "0021-9517",
publisher = "Academic Press Inc.",
}