(41g) An Investigation of Thermal Stability of Pd-Ag Composite Membranes Fabricated By Surfactant Induced Electroless Plating (SIEP) Method for Hydrogen Separation

Hydrogen is considered as an alternative, clean and sustainable energy carrier for reducing the usage of global fossil fuel in large-scale process industries. However, the existing large-scale separation and purification of H₂ for these industries requires large capital investment and production costs. In this regard, Pd- and its alloy based membranes have the potential to play an important role in separation and purification of hydrogen. The dense Pd-Ag composite membranes are particularly attractive for the superior performance in terms of permselectivity and stability compared to pure Pd membranes of similar thickness. In this work, dense Pd-Ag composite membrane on microporous stainless steel (MPSS) substrates were fabricated by sequential deposition of Pd and Ag using surfactant induced electroless plating (SIEP) process, a modified electroless plating process (EP). A cationic surfactant, dodecyl trimethyl ammonium bromide (DTAB), is used to provide a controlled grain-size distribution and agglomeration process. In this work, 4xCMC and 1xCMC of DTAB were used in Pd- and Ag- bath, respectively. Prior to the metal deposition, the MPSS substrates were oxidized at 600 °C for 18 hrs to create an oxide layer as intermetallic diffusion barrier. The membranes fabricated by SIEP method were tested for long term (> 950 hrs) hydrogen permeation measurements at temperatures cycled between 623 K and 723 K. These membranes were characterized by SEM, XRD, EDS and AFM to study physical and morphological features before and after stability tests. The results of these studies will be presented.