It seems like there is a breakthrough a week in the realm of lower-cost catalysts for producing hydrogen. The latest news comes from Ohio State University, where researchers are using a $1.1 million grant to develop alternatives to pricey rare and precious metallic catalysts like platinum and rhodium. With these metals selling for thousands of dollars per ounce, there is a huge incentive to find a replacement made from materials that are readily available. Umit Ozkan, a professor of chemical and biomolecular engineering who leads the research team, and graduate students Hua Song and Lingzhi Zhang, built the catalysts with calcium and cerium oxide covered with a thin layer of cobalt particles. They then pass a heated mixture of ethanol and water over the catalysts in a converter. Hydrogen and carbon dioxide are then produced. The OSU team imagines a scenario where hydrogen converters could be installed at gas stations, producing the gas on demand, thereby eliminating the expense of transporting or piping the gas. Ozkan claims that their method is 90 percent efficient at 660° F, cooler than other processes.
“Whenever a process works at a lower temperature, that brings energy savings and cost savings,” Ozkan says. “Also, if the catalyst is highly active and can achieve high hydrogen yields, we don’t need as much of it. That will bring down the size of the reactor, and its cost.”
Catalyst researchers often face problems such as “coking,” a situation where carbon accumulates on the catalyst. Ozkan’s team says the cerium oxide and calcium solve that problem buy oxidizing the carbon into carbon dioxide. The process also generates carbon monoxide and methane. These gases, along with the CO2, are then removed, and the methane is recovered and fed back into the heating system. Ozkan previously has been noted for working on coal degasification techniques and looking for alternatives to iron-chromium catalysts. Recently, she has also been interviewed about the team’s work on Ira Flatow’s popular Science Friday, which is part of NPR.