121st General Meeting of the KCS

Type Poster Presentation
Area Material Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code MAT.P-432
Subject High loading catalysts in mesopore network of hierarchical zeolites functioning through micropore apertures
Authors Jongho Han, Jangkeun Cho1, Ryong Ryoo2,*
Department of chemistry, Korea Advanced Institute of Science and Technology, Korea
1Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
2Center for Nanomaterials and Chemical Reactions, Institute for Basic Science, Korea
Abstract High loading of metal or metal oxide on a porous support is important for preparing high-performance catalysts. However, loss of dispersion due to sintering and declined mass transfer associated with pore blockage are very common problems for supported catalysts at high catalyst loadings. For the preparation of high loading catalysts with high performance, we synthesized hierarchical zeolites with nanosponge morphologies using zeolite structure-directing surfactants. The obtained zeolites possessed a 3D disordered network of mesopores, which were running through thin frameworks of microporous crystalline zeolite. The mesopores had a narrow distribution of diameters centered at 4 nm. Metal or metal oxide (e.g., Co, Ni and TiO2) nanowire networks filling along the mesopore channels were generated by infiltration of the metal precursors into the mesopores and subsequent treatment of H2 or O2. Despite the tight embedment of the metals or metal oxides that resulted in mesopore blockage, they were readily accessible by the reactants through zeolitic micropores of the mesopore walls encasing them. As a result, the zeolite-supported nanowire networks of Co, Ni, and TiO2 could exhibit quite high catalytic activities for various reactions such as Fischer-Tropsch reaction, hydrogenation, and transfer-hydrogenation, respectively. The catalytic activities were much higher than those of embedded catalysts without micropore apertures. As a representative example, 30 wt% Co loaded on mesoporous zeolite nanosponge exhibited 20-fold higher activity for Fischer-Tropsch reaction under 473 K than 30 wt% Co loaded on MCM-48. We believe that the present approach can be employed to a wide range of metals or metal oxides, aiding the search for more efficient catalysts.
E-mail hanjongho@kaist.ac.kr