Improved Purification Method for Hydrogen

Hydrogen has been labeled by some as the ‘perfect fuel alternative’. It is considered the best pollution-free alternative to batteries and hydrogen-powered fuel cells hold enormous promise as a power source for a future generation of cars.

The biggest hurdle in using hydrogen as a fuel source is it’s purification.

Northwestern University chemist Mercouri G. Kanatzidis, together with postdoctoral research associate Gerasimos S. Armatas, has developed a solution. A new porous material shaped like a honeycomb. This porous honeycombed like structure is very effective at separating hydrogen from gas mixtures. The materials used in constructing hydrogen purification structure are a new family of germanium-rich chalcogenides.

The typical approach to ‘purifying’ hydrogen, i.e., separating the molecules from carbon dioxide and methane, has been based on the size of the molecules. Hydrogen is smaller than these other two gases and while that fact alone allows hydrogen to be separated, the process involves several steps as all three molecules do eventually pass through the same membrane.

Kanatzidis and Armatas have decided to skip the membrane filtration method in favor of a polarization method. Hydrogen molecules have a less affinity to the honeycomb material than do other gases and therefore pass through more readily. This process involves fewer steps therefore making the process more efficient.

According to Kanatzidis, another advantage of the process is “convenient temperature range.” which varies from zero degrees Celsius to room temperature!