Heterogeneous Metal-Free Hydrogenation over Defect-Laden Hexagonal Boron Nitride

Journal Article · Wed Dec 21 00:00:00 EST 2016 · ACS Omega

DOI:https://doi.org/10.1021/acsomega.6b00315· OSTI ID:1336965

Nash, David J. ^[1]; Restrepo, David T. ^[1]; Parra, Natalia S.; Giesler, Kyle E.; Penabade, Rachel A.; Aminpour, Maral; Le, Duy; Li, Zhanyong  ^[2]; Farha, Omar K.  ^[2]; Harper, James K. ^[1]; Rahman, Talat S.; Blair, Richard G.

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1. Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 32816, United States
2. Department of Chemistry, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States

Catalytic hydrogenation is an important process used for the production of everything from foods to fuels. Current heterogeneous implementations of this process utilize metals as the active species. Until recently, catalytic heterogeneous hydrogenation over a metal-free solid was unknown; implementation of such a system would eliminate the health, environmental, and economic concerns associated with metal-based catalysts. We report good hydrogenation rates and yields for a metal-free heterogeneous hydrogenation catalyst as well as its unique hydrogenation mechanism. We achieved catalytic hydrogenation of olefins over defect-laden h-BN (dh-BN) in a reactor designed to maximize the defects in h-BN sheets. Good yields (>90%) and turnover frequencies (6 × 10^–5–4 × 10^–3) were obtained for the hydrogenation of propene, cyclohexene, 1,1-diphenylethene, (E)- and (Z)-1,2-diphenylethene, octadecene, and benzylideneacetophenone. Temperature-programmed desorption of ethene over processed h-BN indicates the formation of a highly defective structure. Solid-state NMR (SSNMR) measurements of dh-BN with high and low propene surface coverages show four different binding modes. The introduction of defects into h-BN creates regions of electronic deficiency and excess. Density functional theory calculations show that both the alkene and hydrogen-bond order are reduced over four specific defects: boron substitution for nitrogen (B_N), vacancies (V_B and V_N), and Stone–Wales defects. SSNMR and binding-energy calculations show that V_N are most likely the catalytically active sites. Our work shows that catalytic sites can be introduced into a material previously thought to be catalytically inactive through the production of defects.

• Research Organization: Univ. of Central Florida, Orlando, FL (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-07ER15842
• OSTI ID: 1336965
• Alternate ID(s): OSTI ID: 1339948
• Journal Information: ACS Omega, Journal Name: ACS Omega Vol. 1 Journal Issue: 6; ISSN 2470-1343
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Catalysts
Hydrogenation
Organic compounds and Functional groups
Quantum mechanical methods