Effect of post-sputter polishing on the performance of a disc-shaped Pd/ZrO2/Ni hydrogen membrane

A thin and highly selective Pd/ZrO2/Ni membrane (Pd layer: 3.4-3.7 mu m) was fabricated using repetitive cycles of sputtering and polishing processes without any further thermal treatment. Based on the results of a vacuum leak test through the membrane, the polishing step could effectively eliminate some of the defects formed between Pd columns by filling and surface flattening. The prepared Pd membrane exhibited a high hydrogen permeation flux (31.7 ml/min/cm(2)) and a significantly high H-2/N-2 selectivity at del-P = 1 bar and 400 degrees C. The membrane selectivity remained significantly high (24,157 at del-P = 20 bar) even under a large pressure difference. (C) 2016 Elsevier B.V. All rights reserved.