Characterization of Pd 60 Cu 40 Composite Membrane Prepared by a Reverse Build-Up Method for Hydrogen Purification

A thin Pd-based H 2 -permeable membrane is required to produce high-purity H 2 with high efficiency. In this study, a porous Ni-supported Pd 60 Cu 40 composite H 2 -permeable membrane was developed using a reverse build-up method to produce economical H 2 purification. The thickness of the Pd 60 Cu 40 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, H 2 permeation test, and Auger microprobe analysis. The permeation tests were performed at 300–320 °C and 50–100 kPa with H 2 introduced from the primary side. The H 2 permeation flux was stable up to ~320 °C. The n -value was determined to be 1.0. The H 2 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 Pd 60 Cu 40 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 Pd 60 Cu 40 membrane.