Millimetric MOF-Pt hybrid catalyst for size-selective hydrogenation

Shape and size selectivity is a vital consideration for many industrial heterogeneous catalysts, which often lack the ability to convert specific molecules in a mixture of reactants, including catalyst poisons. Among MOFs, the zeolitic imidazolate frameworks (ZIFs), a sub-family constructed around imidazolate linkers,[1] show the high chemical stability required for applications in catalysis. Among ZIF representatives, the SIM-1, formulated as Zn(C10H10N4O2), is isostructural to ZIF-8 with sodalite structure and consists in Zn tetrahedra linked by carboxylimidazolate linkers. It presents a small pore diameter around 7.5 A and narrow windows of ca. 5 A.[2] The SIM-1 already demonstrated its wide versatility and efficiency for gas adsorption,[3] gas separation[4] and liquid phase heterogeneous catalysis.[5] Here we report the direct in situ SIM-1 film growth for the first time on platinum-loaded millimetric alumina beads (Figure 1).[6] In contrast to reported multistep growth of MOF layer on metal nanocrystals, we developed an easily scalable and widely applicable methodology to overlay catalytic objects with a MOF membrane. The supported SIM-1 layer is demonstrated to act as a molecular sieve when the SIM-1@Pt/Al2O3 beads are involved in Pt-catalyzed reactions. This hybrid material exhibits size-selective discrimination, as the hydrogenation of toluene could be totally suppressed, while ethylene conversion was hardly affected. The simple methodology reported here opens new perspectives in the design of shaped and highly selective hybrid core-shell catalytic solids. [1]a) R. Banerjee, H. Furukawa, D. Britt, C. Knobler, M. O'Keeffe, O. M. Yaghi, J. Am. Chem. Soc. 2009, 131, 3875; b) R. Banerjee, A. Phan, B. Wang, C. Knobler, H. Furukawa, M. O'Keeffe, O. M. Yaghi, Science 2008, 319, 939; c) K. S. Park, Z. Ni, A. P. Cote, J. Y. Choi, R. D. Huang, F. J. Uribe-Romo, H. K. Chae, M. O'Keeffe, O. M. Yaghi, Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 10186-10191. [2]M. Baias, A. Lesage, S. Aguado, J. Canivet, V. Moizan-Basle, N. Audebrand, D. Farrusseng, L. Emsley, Angew. Chem. Int. Ed. 2015, 54, 5971-5976. [3]H. Amrouche, S. Aguado, J. Perez-Pellitero, C. Chizallet, F. Siperstein, D. Farrusseng, N. Bats, C. Nieto-Draghi, J. Phys. Chem. C 2011, 115, 16425-16432. [4]a) S. Aguado, J. Canivet, D. Farrusseng, J. Mater. Chem. 2011, 21, 7582-7588; b) S. Aguado, C. H. Nicolas, V. Moizan-Basle, C. Nieto, H. Amrouche, N. Bats, N. Audebrand, D. Farrusseng, New J. Chem. 2011, 35, 41-44. [5]a) S. Aguado, J. Canivet, D. Farrusseng, Chem. Commun. 2010, 46, 7999-8001; b) S. Aguado, J. Canivet, Y. Schuurman, D. Farrusseng, J. Catal. 2011, 284, 207-214; c) J. Canivet, S. Aguado, C. Daniel, D. Farrusseng, ChemCatChem 2011, 3, 675-678. [6] Sonia Aguado, Sawsan El-Jamal, Frederic Meunier, Jerome Canivet and David Farrusseng, Submitted