Comparison of Pt and Pd catalysts for hydrogen pump separation from reformate

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• 作者：Xuemei Wu ; Jay Benziger ; Gaohong He
• 关键词：Hydrogen purification ; Electrochemical separations ; Electrocatalyst coated membranes
• 刊名：Journal of Power Sources
• 出版年：2012
• 出版时间：15 November, 2012
• 年：2012
• 卷：218
• 期：Complete
• 页码：424-434
• 全文大小：1155 K

文摘

Hydrogen recovery from CO₂/H₂ reformate mixtures by selective electrochemical pumping was compared from carbon supported Pt and Pd catalysts. Catalyst coated membranes were prepared by air-brushing a suspension of commercially available 20?wt % Pt/C or 20?wt % Pd/C catalysts and solubilized Nafion in methanol onto Nafion 115 membranes. Electrochemical activity and separation efficiency for the different catalyst layer formulations were evaluated by cyclic voltammetry, polarization and potentiostatic hydrogen pumping. The effective membrane-electrode-assembly (MEA) resistance increased due to dilution of H₂ by CO₂; the effective MEA resistance was greater for Pd/C catalysts than for Pt/C catalysts. CO₂ adsorbed more strongly to Pd catalysts than Pt catalysts reducing the electrochemical active surface area available for hydrogen oxidation/reduction. Pd/C catalysts had an energy efficiency for hydrogen recovery from reformate mixtures approximately 80 % that of Pt catalysts. Because Pd is ten times less costly than Pt the results presented here suggest that Pd/C catalysts would be a promising candidate for hydrogen pumps to recover H₂ from reformate mixtures.