Power Generation

Researchers at Ohio State University have developed a new catalyst that makes hydrogen from ethanol at 90% efficiency at 350^oC (a low temperature by industrial standards). The catalyst is made from tiny granules of cerium oxide, a common ingredient in industrial ceramics, and calcium covered by even smaller particles of cobalt. It also has the added benefit of being much less expensive to produce and use, as unlike similar catalysts under investigation, it does not contain precious metals such as platinum or rhodium.

“Rhodium is used most often for this kind of catalyst, and it costs $9000 an ounce”, says Umit Ozcan, Professor of chemical and biomolecular engineering and lead researcher on the project, “Our catalyst costs $9 a kilogram.”

During the process, a liquid biofuel, such as ethanol is heated and pumped into a reactor where, combined with the catalyst, a series of chemical reactions convert the fuel into a hydrogen-rich gas. The researchers have overcome the problem of catalyst ‘coking’ (where tiny particles of carbon form on the surface of the catalyst and stop it working) by the combination of chemicals used, which promote the movement of oxygen ions within the catalyst, forming CO₂, rather than free carbon. At the end of the process, waste gases such as CO₂, CO and methane are removed and the hydrogen is purified. The process is made more energy efficient by capturing the waste heat with heat exchangers and pumping back into the reactor. The recovered methane can also be used to supply part of the energy for the process.

Ozkan says the newly developed catalyst could be used in a ‘distributed production’ strategy, “Instead of making hydrogen from biofuel at a centralized facility and transporting it to gas stations, we could use our catalyst inside reactors that are actually located at the gas stations. So we wouldn’t have to transport or store the hydrogen – we could store the biofuel and make hydrogen on the spot”.

Ozkan’s team is now studying how to use the same catalyst with other liquid biofuels.

For further information: http://researchnews.osu.edu/archive/biohydro.htm