Effects of Sn residue on the high temperature stability of the H_2-permeable palladium membranes prepared by electroless plating on Al_2O_3 substrate after SnCl_2–PdCl_2 process: A case study  

作　　者：Lei Wei Jian Yu Xiaojuan Hu Rongxia Wang Yan Huang 

机构地区：[1]State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University

出　　处：《Chinese Journal of Chemical Engineering》2016年第9期1154-1160,共7页中国化学工程学报（英文版）

基　　金：Supported by the National High Technology Research and Development Program of China(863 Program,2009AA05ZI03);the Natural Science Foundation of Jiangsu Province(BK 20130940,BK 20130916);the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)

摘　　要：The stability of composite palladium membranes is of key importance for their application in hydrogen energy systems. Most of these membranes are prepared by electroless plating, and beforehand the substrate surface is activated by a SnCl_2–PdCl_2 process, but this process leads to a residue of Sn, which has been reported to be harmful to the membrane stability. In this work, the Pd/Al_2O_3 membranes were prepared by electroless plating after the SnCl_2–PdCl_2 process. The amount of Sn residue was adjusted by the SnCl_2 concentration, activation times and additional Sn(OH)_2coating. The surface morphology, cross-sectional structure and elemental composition were analyzed by scanning electron microscopy(SEM), metallography and energy dispersive spectroscopy(EDS), respectively. Hydrogen permeation stability of the prepared palladium membranes were tested at450–600 °C for 400 h. It was found that the higher SnCl_2 concentration and activation times enlarged the Sn residue amount and led to a lower initial selectivity but a better membrane stability. Moreover, the additional Sn(OH)_2coating on the Al_2O_3 substrate surface also greatly improved the membrane selectivity and stability.Therefore, it can be concluded that the Sn residue from the SnCl_2–PdCl_2 process cannot be a main factor for the stability of the composite palladium membranes at high temperatures.The stability of composite palladium membranes is of key importance for their application in hydrogen energy systems. Most of these membranes are prepared by electroless plating, and beforehand the substrate surface is activated by a SnCl2–PdCl2 process, but this process leads to a residue of Sn, which has been reported to be harmful to the membrane stability. In this work, the Pd/Al2O3 membranes were prepared by electroless plating after the SnCl2–PdCl2 process. The amount of Sn residue was adjusted by the SnCl2 concentration, activation times and additional Sn（OH）_2coating. The surface morphology, cross-sectional structure and elemental composition were analyzed by scanning electron microscopy（SEM）, metallography and energy dispersive spectroscopy（EDS）, respectively. Hydrogen permeation stability of the prepared palladium membranes were tested at450–600 ℃ for 400 h. It was found that the higher SnCl2 concentration and activation times enlarged the Sn residue amount and led to a lower initial selectivity but a better membrane stability. Moreover, the additional Sn（OH）2coating on the Al2O3 substrate surface also greatly improved the membrane selectivity and stability.Therefore, it can be concluded that the Sn residue from the SnCl2–PdCl2 process cannot be a main factor for the stability of the composite palladium membranes at high temperatures.

关 键 词：Hydrogen separation Composite palladium membrane Electroless plating SnCl2–PdCl2 process Sn residue Membrane stability 

分 类 号：TQ051.893[化学工程]