製作陶瓷─鈀/鎳的複合薄膜用於氫氣分離

Abstract

本研究利用可導質子的緻密氧化物及可透氫的鈀鎳合金所組成的管狀複合薄膜於中高溫分離氫氣和二氧化碳，首先，利用燃燒法製備兩種不同結構的氧化物Perovskite結構的BaCe0.9-xZrxGd0.1O3-α和Pyrochlore結構的La2-xSmxCe2O7。其中BaCe0.4Zr0.5Gd0.1O3-α在600℃下可完全不與二氧化碳反應，而La2-xSmxCe2O7 (x = 0.03~0.07)則皆不反應，兩者粒徑尺寸為400~500 nm。另一方面，使用逐步還原法(successive reduction method)合成尺寸大小20 nm的鈀鎳核殼型奈米粒子，後續熱處理製程中將形成均勻鈀鎳合金，鈀鎳重量比約為82:18，為透氫和導電子的介質。混合金屬與氧化物並加入黏著劑與分散劑以調配成漿料，冺用沉浸法(dip-coating)於多孔陶瓷管上進行鍍膜，利用氣相層析儀作薄膜漏氣測試後，發現目前的研究成果展現薄膜氣密性仍需補強，為0.0298 cm3/min〃cm2的氬氣測試漏氣量。此外，在基底和薄膜間亦利用沉浸法塗佈氧化鋁緩衝層，以減緩多孔基底表面凹凸起伏程度，以得到厚度更均勻的薄膜。

This work is concerned with the fabrication of a composite cermet membrane that allows the permeation of hydrogen from a mixture gas of hydrogen and carbon dioxide. The composite membrane contains perovskite and pyrochlore that are mixed intimately with nanoparticles of PdNi. We prepare the ceramics (BaCe0.9-xZrxGd0.1O3-α and La2-xSmxCe2O7) via a combustion method and determine their chemical stability against carbon dioxide ambient. The PdNi nanoparticles in 20 nm sizes are synthesized by a successive reduction method and undergo a annealing process to form alloyed PdNi phase. Both ceramics and PdNi nanoparticles are dispensed in suitable additives to form a slurry that is cast on a porous ceramic tube by dip coating method. The cermet deposit is sintered to form an integral film for hydrogen permeation purpose. Unfortunately, the sample fails in the leakage test and it is possible that residual cracks in the cermets might lead to the failed results.