Characterization of sulfur resistance of Pd/Au hydrogen separation membrane prepared by galvanic displacement

Sulfur containing impurities are known to cause severe and irreversible poisoning of Pd membranes during the hydrogen separation application (Especially in the coal gasification) resulting in the reduction of hydrogen permeability, selectivity and structure deterioration of Pd membranes. Pd/Au alloys are found to show high sulfur resistance in comparison to pure Pd and other Pd based alloys (i.e., Pd/Ag, Pd/Cu, etc.) in addition to its high hydrogen permeability. As a result, Pd/Au alloys have recently regained great interests for membrane separation process. The preparation of Pd/Au alloys can be carried out by the galvanic displacement method, which does not require external sources of current, reducing agent and complexing agent (such as cyanide) and provides simplified plating equipment and environmentally preferable procedure. The main objectives of this study were to investigate the effect of temperature on sulfur poisoning of pure Pd and Pd/Au alloy morphologically. In addition, the hydrogen permeation characteristics of the Pd/Au membrane in the presence of H2S and the permeance recovery after the sulfur poisoning at different temperatures were investigated.