具有空隙结构的钯复合膜的制备与研究

Fabrication and testing of Pd composite membranes with a novel gap structure

钯膜在氢气分离、纯化及燃料电池氢源等方面有显著的应用前景,尤其是针对燃料电池氢源技术快速响应的需求,需要进一步开发高透氢性能和高稳定性的钯复合膜。对此,本文提出了一种简捷可行的具有空隙结构的钯复合膜制备思路,即在陶瓷或不锈钢基底表面采用MnCO3进行修饰,制备钯复合膜后再加热使MnCO3分解的方法,在金属钯膜和基底之间形成一层1μm左右的空隙。分析测试表明,该修饰方法不仅得到了高透氢性能的钯复合膜,而且采用该空隙结构的陶瓷及不锈钢负载钯复合膜在150~400℃的14~20个快速升降温循环中,展现了良好的稳定性,而不使用该空隙结构的常规陶瓷负载钯复合膜的透氢量严重下降;该空隙结构能实现升降温过程中钯膜的自由伸缩,并避免与基底之间的相互作用及由于热膨胀系数不一致造成的剪切应力,进而保证钯复合膜的快速升降温稳定性,能应用于陶瓷及不锈钢等多种基底,具有良好的应用前景。

Pd-based membranes show great potential in the field of H2 separation, purification as well as H2 production for fuel cell applications. In order to meet the need of fast response during startup/shutdown process of fuel cells, it is necessary to further develop Pd composite membranes with high hydrogen permeability and high stability. A facile approach is provided in this study which allows a small gap of around 1 μm between Pd metal layer and ceramic or stainless steel substrate, obtained by MnCO3 modification and subsequent decomposition under thermal treatment after Pd plating. Analysis results show that such a gap ensures high hydrogen permeance of Pd composite membranes due to minimized support resistance, as well as high stability during 14 to 20 fast heating/cooling cycles between 150℃ and 400℃. On the contrary, the hydrogen permeance of conventional Pd composite membranes suffered a great decline during similar temperature cycles. This structural design ensures the free expansion and contraction of Pd metal layer during thermal treatment, and avoids the chemical/physical interaction between Pd metal layer and substrate as well as accompanied shear stress at the interface due to difference in thermal expansion coefficients. It shows great universality in a variety of substrates, and is thus expected to play an important role in future applications.