Manufacture of High-Purity Hydrogen

An existing industrial application of the ultrapure hydrogen separated by dense Pd alloy membranes is for electronics industry. In the fabrication of silicon chips, hydrogen acts as a carrier to transport small quantities of vaporized chemical compounds required to dope the chip to the surface of the silicon wafer [Philpott and Coupland, 1988]. The hydrogen used must be of a very high purity. The membrane units are used not only for gas purification but also for hydrogen recovery from hydrogen rich gas streams. 

For many industrial bulk processing applications, the purity of the hydrogen required can not justify the use of dense palladium or its alloy membranes due to their low permeabilities. In these cases, porous inorganic membranes are more often considered. 

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