Universal and Versatile Route for Selective Covalent Tethering of Single-Site Catalysts and Functional Groups on the Surface of Ordered Mesoporous Carbons
journal contributionposted on 13.05.2014, 00:00 by Madhura Joglekar, Svitlana Pylypenko, Megan M. Otting, Justin S. Valenstein, Brian G. Trewyn
A 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.