Synthesis, Annealing, and Performances of Pd鈥揂u Asymmetric Composite Membranes for Hydrogen Purification

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• 作者：Yi Hua Ma ; Chao-Huang Chen ; Jacopo Catalano ; Federico Guazzone ; E. Andrew Payzant
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：July 3, 2013
• 年：2013
• 卷：52
• 期：26
• 页码：8732-8744
• 全文大小：630K
• 年卷期：v.52,no.26(July 3, 2013)
• ISSN：1520-5045

文摘

Composite asymmetric Pd鈥揂u membranes were prepared on porous Inconel and Hastelloy tubular supports by electroless deposition and galvanic displacement techniques and tested both before and after Au deposition in pure H₂ atmosphere. The final membranes with average Au bulk content up to 16.7 wt % were 9鈥?5 渭m thick and showed H₂/He ideal selectivities in excess of 900 for the entire period of their characterization. The annealing of the as-prepared membranes was conducted through the coating and diffusion mechanism in He and H₂ atmospheres at 500 掳C. The annealing conditions were chosen after nonisothermal and isothermal HT-XRD studies were carried out on Pd鈥揂u coupons prepared with the same techniques used for the membranes fabrication. After the formation of the Pd鈥揂u layer, the membranes showed steady H₂ flux and stable Au gradient on the membrane top layer. Comparisons between permeance for Pd鈥揂u and pure Pd membranes indicated that the membranes with an average Au bulk content of 4.5 and 5.4 wt % had an enhancement up to 20% of the H₂ permeability with respect to pure Pd membranes in the temperature range 250鈥?50 掳C. On the other hand, the membrane having the highest Au concentration, even though characterized by a lower H₂ permeability (77% of pure Pd), had a rather high surface Au content (approximately 46 wt %), which might improve the tolerance against H₂S poisoning.