TY - JOUR
T1 - Zr6O8 node-catalyzed butene hydrogenation and isomerization in the metal−organic framework NU-1000
AU - Hicks, Kenton E.
AU - Rosen, Andrew S.
AU - Syed, Zoha H.
AU - Snurr, Randall Q.
AU - Farha, Omar K.
AU - Notestein, Justin M.
N1 - Funding Information:
This work was supported as part of the Inorganometallic Catalyst Design Center, an EFRC funded by the DOE, Office of Science, Basic Energy Sciences under award number DE-SC0012702. The material in this work is also supported by the Institute for Catalysis in Energy Processes (ICEP) via the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-FG02-03ER15457. This work made use of the IMSERC X-ray facility at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), and Northwestern University. This work made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-1542205), the IIN, and Northwestern’s MRSEC program (NSF DMR-1720139). This work made use of the Keck-II facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern’s MRSEC program (NSF DMR-1720139). The REACT Core facility acknowledges funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Catalysis Science program (DE-SC0001329 and DE-FG02-03ER15457) used for the purchase of the Altamira BenchCat 4000 and the Thermo-iS50 infrared spectrometer, respectively. A.S.R. was supported by a fellowship award through the National Defense Science and Engineering Graduate (NDSEG) Fellowship Program and a Ryan Fellowship through the International Institute for Nanotechnology at Northwestern University. Z.H.S. was supported by the National Science Foundation (NSF) Graduate Research Fellowship under Grant No. (DGE-1842165). The authors acknowledge computing support from the Quest high-performance computing facility at Northwestern University and the Extreme Science and Engineering Discovery Environment (XSEDE) Stampede2 through allocation CTS180057 supported by the National Science Foundation grant number ACI-1548562. The authors thank Prof. Neil Schweitzer and Dr. Selim Alayoglu for facilitating instrument use in the REACT core facility and for helpful discussions.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/12/18
Y1 - 2020/12/18
N2 - Zirconium-based metal−organic frameworks (Zr-MOFs) have been increasingly studied over the past two decades as heterogeneous catalysts due to their synthetic tunability, well-defined nature, and chemical stability. In contrast to traditional zirconia-based heterogeneous catalysts, the community has assumed that Zr-MOFs are inert catalyst supports that do not participate directly in hydrocarbon transformations, such as olefin hydrogenation and isomerization. Here, we report that the Zr-MOF NU-1000 is capable of catalyzing olefin hydrogenation and isomerization, without any postsynthetic modifications, under a hydrogen atmosphere. We probe H2 activation over the nodes of NU-1000 via spectroscopic and computational techniques revealing that H2 dissociation can occur heterolytically across coordinatively unsaturated Zr sites and proximal hydroxide and μ3-oxo ligands. These results, along with catalytic experiments, suggest that H2 activation results in node-supported zirconium hydrides capable of the hydrogenation and isomerization of 1-butene. When examining rate dependence on the partial pressure of H2, we observe first-order dependence for hydrogenation and half-order dependence for isomerization. Half-order H2 rate dependence is consistent with a mechanism where both fragments of cleaved H2 are active for 1-butene isomerization, suggesting that heterolytic cleavage generates acidic protons resulting in parallel, acid-, and hydride-catalyzed isomerization pathways. This work shows that Zr-MOFs have more diverse reactivity than the current literature may suggest and opens possibilities for ways in which Zr-MOFs can be used as heterogeneous catalysts and supports.
AB - Zirconium-based metal−organic frameworks (Zr-MOFs) have been increasingly studied over the past two decades as heterogeneous catalysts due to their synthetic tunability, well-defined nature, and chemical stability. In contrast to traditional zirconia-based heterogeneous catalysts, the community has assumed that Zr-MOFs are inert catalyst supports that do not participate directly in hydrocarbon transformations, such as olefin hydrogenation and isomerization. Here, we report that the Zr-MOF NU-1000 is capable of catalyzing olefin hydrogenation and isomerization, without any postsynthetic modifications, under a hydrogen atmosphere. We probe H2 activation over the nodes of NU-1000 via spectroscopic and computational techniques revealing that H2 dissociation can occur heterolytically across coordinatively unsaturated Zr sites and proximal hydroxide and μ3-oxo ligands. These results, along with catalytic experiments, suggest that H2 activation results in node-supported zirconium hydrides capable of the hydrogenation and isomerization of 1-butene. When examining rate dependence on the partial pressure of H2, we observe first-order dependence for hydrogenation and half-order dependence for isomerization. Half-order H2 rate dependence is consistent with a mechanism where both fragments of cleaved H2 are active for 1-butene isomerization, suggesting that heterolytic cleavage generates acidic protons resulting in parallel, acid-, and hydride-catalyzed isomerization pathways. This work shows that Zr-MOFs have more diverse reactivity than the current literature may suggest and opens possibilities for ways in which Zr-MOFs can be used as heterogeneous catalysts and supports.
KW - Heterogeneous catalysis
KW - Hydrogen dissociation
KW - Metal−organic framework
KW - Olefin hydrogenation
KW - Olefin isomerization
KW - Zirconium
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U2 - 10.1021/acscatal.0c03579
DO - 10.1021/acscatal.0c03579
M3 - Article
AN - SCOPUS:85097734725
VL - 10
SP - 14959
EP - 14970
JO - ACS Catalysis
JF - ACS Catalysis
SN - 2155-5435
IS - 24
ER -