Characterization of Pd60Cu40 Composite Membrane Prepared by a Reverse Build-Up Method for Hydrogen Purification

Abstract

A thin Pd-based H2-permeable membrane is required to produce high-purity H2 with high efficiency. In this study, a porous Ni-supported Pd60Cu40 composite H2-permeable membrane was developed using a reverse build-up method to produce economical H2 purification. The thickness of the Pd60Cu40 alloy layer produced by the improved membrane production process reached 1.0 μm; it was thinner than the layer obtained in a previous study (3.7 μm). The membrane was characterized by scanning electron microscope, inductively coupled plasma optical emission spectrometer, H2 permeation test, and Auger microprobe analysis. The permeation tests were performed at 300–320 °C and 50–100 kPa with H2 introduced from the primary side. The H2 permeation flux was stable up to ~320 °C. The n-value was determined to be 1.0. The H2 permeance of the membrane was 2.70 × 10−6 mol m−2 s−1 Pa−1.0 at 320 °C, after 30 h, similar to those of other 2.2-µm-thick and 3.7-µm-thick Pd60Cu40 composite membranes, suggesting that the adsorption and dissociation reaction processes on the PdCu alloy surface were rate-limiting. The Pd cost of the membrane was estimated to be ~1/30 of the Pd cost of the pure Pd60Cu40 membrane.