TY - JOUR
T1 - Stable metal-organic framework-supported niobium catalysts
AU - Ahn, Sol
AU - Thornburg, Nicholas E.
AU - Li, Zhanyong
AU - Wang, Timothy C.
AU - Gallington, Leighanne C.
AU - Chapman, Karena W.
AU - Notestein, Justin M.
AU - Hupp, Joseph T.
AU - Farha, Omar K.
N1 - Funding Information:
O.K.F., K.W.C., and J.T.H. gratefully acknowledge the financial support from the Inorganometallic Catalyst Design Center, an EFRC funded by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (DE-SC0012702). J.M.N. and N.E.T. acknowledge funding from the Dow Chemical Company. This work made use of the J. B. Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1121262) at the Materials Research Center of Northwestern Univ. This work also made use of the EPIC facility (NUANCE Center-Northwestern University), which has received support from the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); and the State of Illinois, through the IIN. This research used resources of the Advanced Photon Source, a DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DEAC02-06CH11357.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/11/21
Y1 - 2016/11/21
N2 - Developing structurally well-defined, supported oxide catalysts remains a significant challenge. Here, we report the grafting of Nb(V) oxide sites onto the nodes of the Zr-based metal organic framework (MOF) NU-1000 as a stable, well-defined catalyst support. Nb(V) oxide was deposited with loadings up to 1.6 mmol/g via two postsynthetic methods: atomic layer deposition in a MOF, and solution-phase grafting in a MOF. Difference envelope density measurements indicated that the two synthetic methods resulted in different local structures of the Nb(V) ions within NU-1000. Despite their high Nb(V) loadings, which were equivalent to >60% surface coverage, nearly all Nb(V) sites of the MOF-supported catalysts were active sites for alkene epoxidation, as confirmed by phenylphosphonic acid titration. The MOF-supported catalysts were more selective than the control Nb-ZrO2 catalyst for cyclohexene epoxidation with aqueous H2O2 and were far more active on a gravimetric basis.
AB - Developing structurally well-defined, supported oxide catalysts remains a significant challenge. Here, we report the grafting of Nb(V) oxide sites onto the nodes of the Zr-based metal organic framework (MOF) NU-1000 as a stable, well-defined catalyst support. Nb(V) oxide was deposited with loadings up to 1.6 mmol/g via two postsynthetic methods: atomic layer deposition in a MOF, and solution-phase grafting in a MOF. Difference envelope density measurements indicated that the two synthetic methods resulted in different local structures of the Nb(V) ions within NU-1000. Despite their high Nb(V) loadings, which were equivalent to >60% surface coverage, nearly all Nb(V) sites of the MOF-supported catalysts were active sites for alkene epoxidation, as confirmed by phenylphosphonic acid titration. The MOF-supported catalysts were more selective than the control Nb-ZrO2 catalyst for cyclohexene epoxidation with aqueous H2O2 and were far more active on a gravimetric basis.
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U2 - 10.1021/acs.inorgchem.6b02103
DO - 10.1021/acs.inorgchem.6b02103
M3 - Article
C2 - 27797182
AN - SCOPUS:84997816064
SN - 0020-1669
VL - 55
SP - 11954
EP - 11961
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 22
ER -