(696f) Palladium-Silver Composite Membranes: A Novel Method for Synthesis

Synthesis of palladium-silver (PdAg) composite membranes via electroless plating is traditionally done with the bath stabilizer ethylenediaminetetraacetic acid (EDTA) [1-3]. EDTA has been shown to remain in the membrane and cause contamination during mixed gas testing [4, 5]. A novel process for the co-plating of PdAg has been developed that does not include EDTA in the electroless plating baths. Based on bath compositions and weight gain, an estimated 3.6 micron thick Pd₈₈Ag₁₂ composite membrane has been made on a ceramic support. Preliminary pure gas permeation testing has shown promising results. The membrane was annealed for 20 hours at 550 °C, with pre-annealing testing done at 400 °C. Both data sets are shown in Figure 1 below. The hydrogen flux increased by a factor of 2.5 after annealing for the highest pressure tested. The synthesized Pd₈₈Ag₁₂ membrane has comparable fluxes at 300 °C and 400 °C to membranes of similar thicknesses and compositions as previously reported by Tanaka, et al [6] and Uemiya [7], respectively. 1. Kikuchi, E. and S. Uemiya, Preparation of supported thin palladium-silver alloy membranes and their characteristics for hydrogen separation. Gas Separation & Purification. 5(4):(1991) p. 261-266. 2. Bhandari, R. and Y.H. Ma, Pd-Ag membrane synthesis: The electroless and electro-plating conditions and their effect on the deposits morphology. Journal of Membrane Science. 334(1-2):(2009) p. 50-63. 3. Witjens, L.C., et al., Improving the control of the electroless plating synthesis of Pd/Ag membranes for hydrogen separation using Rutherford backscattering. Journal of Membrane Science. 254(1-2):(2005) p. 241-248. 4. Collins, J.P., et al., Catalytic Dehydrogenation of Propane in Hydrogen Permselective Membrane Reactors. Industrial & Engineering Chemistry Research. 35(12):(1996) p. 4398-4405. 5. Volpe, M., et al., Optimized bath for electroless deposition of palladium on amorphous alumina membranes. Surface and Coatings Technology. 200(20-21):(2006) p. 5800-5806. 6. Pacheco Tanaka, D.A., et al., Preparation of palladium and silver alloy membrane on a porous [alpha]-alumina tube via simultaneous electroless plating. Journal of Membrane Science. 247(1-2):(2005) p. 21-27. 7. Uemiya, S., T. Matsuda, and E. Kikuchi, Hydrogen permeable palladium-silver alloy membrane supported on porous ceramics. Journal of Membrane Science. 56(3):(1991) p. 315-325.