Characterization of Pd60 Cu40 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 Pd60 Cu40 composite H2-permeable membrane was developed using a reverse build-up method to produce economical H2 purification. The thickness of the Pd60 Cu40 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 character-ized 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 Pd60 Cu40 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 Pd60 Cu40 membrane.