催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (6): 711-715.

• 研究论文 • 上一篇    

高透量 PdAu/陶瓷复合膜的表征与性能评测

史蕾 1, 2, 曾高峰 1,2, 徐恒泳 1   

  1. 1 中国科学院大连化学物理研究所, 辽宁大连 116023 2 中国科学院研究生院, 北京 100049
  • 收稿日期:2010-06-25 出版日期:2010-06-25 发布日期:2013-12-05

Characterization and Performance of High-Flux PdAu/Ceramic Composite Membranes

SHI Lei1, 2, ZENG Gaofeng1, 2, XU Hengyong1,*   

  1. 1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China 2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2010-06-25 Online:2010-06-25 Published:2013-12-05

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摘要： 采用化学镀方法在非对称氧化铝管状载体上制备出高性能 PdAu 合金膜. 采用阶段性热处理方法通过 X 射线衍射技术监测 PdAu 膜层合金化进程, 发现在 823 K 下 H2 气氛中厚度为 2 μm, Au 含量为 17.37% 的 PdAu 双金属膜层需要 200 h 达到完全合金化; N2/H2 气氛对 PdAu 合金化速率无显著影响, 但 N2 气氛中合金化后的 PdAu 合金膜表面粒子烧结更为严重. 在 623~823 K 下, 与未进行化学镀 Au 时的纯 Pd 膜相比, PdAu 合金膜的 H2 渗透速率平均增加 1.68 倍, 透氢活化能 (Ea) 降低 38.51%; 当温度低于 573 K 时, PdAu 合金膜的 Ea 由高温时的 8.83 kJ/mol 增加到 15.75 kJ/mol, 此时 PdAu 合金膜的 H2 渗透控速步骤由体相扩散为主的 H2 传质步骤过渡到由表面扩散为主的传质步骤. 通过扫描电镜和能谱联用仪对 PdAu 合金膜的膜厚度和截面组成进行了表征. 关键词

关键词: 化学镀, 无氰化学镀金, 钯金复合膜, 钯金合金, 氢渗透

Abstract: A PdAu membrane was prepared by sequential electroless plating of Pd and Au onto the outside surface of porous 冏-Al2O3 substrate followed by annealing and H2/N2 performance evaluation. X-ray diffraction was employed to study the PdAu alloy phase formation at 823 K under H2 and N2 atmospheres. Annealing experiments demonstrated that 200 h was needed to form a stoichiometrically homogeneous, 2-m thick Pd82.63Au17.37 membrane from sequentially deposited layers at 823 K and a noticeable particle agglomeration was observed under N2 atmosphere. The performance of the PdAu alloy membrane was evaluated with respect to the H2 flux and permselectivity between 823 and 423 K, which showed that the PdAu alloy membrane had higher H2 flux and lower activation energy than those of pure Pd membrane. The activation energy in the high temperature range is consistent with bulk diffusion-limited H2 transport, while the changes of these charac-teristics at lower temperatures below 573 K indicate desorption or surface limited H2 flux. After the conclusion of gas studies, the PdAu membrane was broken, the thickness and composition of the PdAu layers were determined by SEM and EDX completely.

Key words: electroless plating, cyanide-free electroless gold plating, palladium-gold composite membrane, palladium-gold alloy, hydrogen permeation