Influence of the type of siliceous material used as intermediate layer in the preparation of hydrogen selective palladium composite membranes over a porous stainless steel support
- 作者：J.A. Calles ; joseantonio.calles@urjc.es ; R. Sanz ; D. Alique
- 关键词：Hydrogen separation ; Palladium membrane ; Electroless plating ; Siliceous intermediate layer ; Porous stainless steel support
- 刊名：International Journal of Hydrogen Energy
- 出版年：2012
- 期刊代码：42_03603199
- 类别：ch
- 出版时间：April, 2012
- 卷：37
- 期：7
- 页码：6030-6042
- 文件大小：1706 K
摘要
In this work, several composite membranes were prepared by Pd electroless plating over modified porous stainless steel tubes (PSS). The influence of different siliceous materials used as intermediate layers was analyzed in their hydrogen permeation properties. The addition of three intermediate siliceous layers over the external surface of PSS (amorphous silica, silicalite-1 and HMS) was employed to reduce both roughness and pore size of the commercial PSS supports. These modifications allow the deposition of a thinner and continuous layer of palladium by electroless plating deposition. The technique used to prepare these silica layers on the porous stainless steel tubes is based on a controlled dip-coating process starting from the precursor gel of each silica material. The composite membranes were characterized by SEM, AFM, XRD and FT-IR. Moreover they were tested in a gas permeation set-up to determine the hydrogen and nitrogen permeability and selectivity. Roughness and porosity of original PSS supports were reduced after the incorporation of all types of silica layers, mainly for silicalite-1. As a consequence, the palladium deposition by electroless plating was clearly influenced by the feature of the intermediate layer incorporated. A defect free thin palladium layer with a thickness of ca. 5聽渭m over the support modified with silicalite-1 was obtained, showing a permeance of 1.423路10鈭?聽mol聽m鈭?聽s鈭?聽Pa鈭?.5 and a complete ideal permselectivity of hydrogen.