title: One-Step Synthesis of Zeolite Membranes Containing Catalytic Metal Nanoclusters.
abstract: Metal-loaded zeolitic membranes are promising candidates as catalytic membrane reactors. We report a one-step synthesis method to synthesize zeolite membranes containing metal nanoclusters, that has advantages in comparison to multistep methods such as impregnation and ion exchange. Pure-silica MFI zeolite-Pt hybrid membranes were prepared by hydrothermal synthesis with addition of 3-mercaptopropyl-trimethoxysilane (MPS) and a platinum precursor. Composition analysis and mapping by energy-dispersive X-ray spectroscopy (EDX) reveal that Pt ions/clusters are uniformly distributed along the membrane cross-section. High-magnification scanning transmission electron microscopy (STEM) analysis shows that Pt metal clusters in the hybrid zeolite membrane have a diameter distribution in the range of 0.5-2.0 nm. In contrast, a pure-silica MFI membrane synthesized from an MPS-free solution shows negligible incorporation of Pt metal clusters. To characterize the properties of the hybrid (zeolite/metal) membrane, it was used as a catalytic membrane reactor (CMR) for high-temperature propane dehydrogenation (PDH) at 600 °C and 1 atm. The results indicate that Pt metal clusters formed within the MFI zeolite membrane can serve as effective catalysts for high-temperature PDH reaction along with H2 removal via membrane permeation, thereby increasing both conversion and selectivity in relation to a conventional membrane reactor containing an equivalent amount of packed Pt catalyst in contact with an MFI membrane. The hybrid zeolite-Pt CMR also showed stable conversion and selectivity upon extended high-temperature operation (12 h), indicating that encapsulation in the zeolite allowed thermal stabilization of the Pt nanoclusters and reduced catalyst deactivation.
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: Seok-Jhin
authors: SJ
authors: Kim
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: Shuai
authors: S
authors: Tan
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: Micaela
authors: M
authors: Taborga Claure
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: Laura
authors: L
authors: Briones Gil
authors: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors: Karren L
authors: KL
authors: More
authors: Engineering & Process Sciences, The Dow Chemical Company , 2301 North Brazosport Boulevard, Freeport, Texas 77541, United States.
authors: Yujun
authors: Y
authors: Liu
authors: Engineering & Process Sciences, The Dow Chemical Company , 2301 North Brazosport Boulevard, Freeport, Texas 77541, United States.
authors: Jason S
authors: JS
authors: Moore
authors: Engineering & Process Sciences, The Dow Chemical Company , 2301 North Brazosport Boulevard, Freeport, Texas 77541, United States.
authors: Ravindra S
authors: RS
authors: Dixit
authors: Engineering & Process Sciences, The Dow Chemical Company , 2301 North Brazosport Boulevard, Freeport, Texas 77541, United States.
authors: John G
authors: JG
authors: Pendergast
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: David S
authors: DS
authors: Sholl
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: Christopher W
authors: CW
authors: Jones
authors: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive, Atlanta, Georgia 30332, United States.
authors: Sankar
authors: S
authors: Nair
keywords: MFI; membrane reactor; metal cluster; propane dehydrogenation; zeolite membrane