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Universal and Versatile Route for Selective Covalent Tethering of Single-Site Catalysts and Functional Groups on the Surface of Ordered Mesoporous Carbons
journal contribution
posted on 2014-05-13, 00:00 authored by Madhura Joglekar, Svitlana Pylypenko, Megan
M. Otting, Justin S. Valenstein, Brian G. TrewynA universal and benign strategy for
the surface functionalization
of OMCs through lithium-mediated chemistry has been reported. For
this purpose, a hard templating method for the facile synthesis of
monodispersed ordered mesoporous carbons (OMCs) with well-defined
morphology templated from large pore mesoporous silica nanoparticles
(l-MSN) has been used. These OMCs have high surface
areas (800–1000 m2g–1) and large
pore sizes (4–6 nm) suitable for anchoring bulky inorganic
complexes. It has been demonstrated that the numerous defect sites
present in the graphitic structure of OMCs can be effectively utilized
for selective and covalent tethering of functional groups and single-site
catalysts through lithiation of OMCs. Accordingly, for the first time
a copper-based single-site oxidation catalyst has been covalently
anchored onto the surface of OMCs. This novel system has been thoroughly
characterized with advanced techniques such as electron microscopy,
Raman spectroscopy, thermogravimetric analysis, X-ray diffraction,
and acid–base titrations along with structural insights regarding
the tethered copper catalyst by X-ray photoelectron spectroscopy.
As a proof-of-principle, this active catalytic system has been used
to demonstrate environmentally benign, room temperature selective
oxidation of benzyl alcohol. We envision that this strategy for surface
functionalization would be universal and can be applied for tethering
a variety of different single-site catalysts onto OMCs with high surface
areas. We also believe that it would have a direct impact on the currently
available limited syntheses and surface functionalization techniques
of mesoporous carbons for catalytic, electrocatalytic, and biological
applications.