Scientists use iron instead of platinum to make hydrogen
(Kitco News) - Platinum group metal companies are looking to hydrogen power as a potential bridge to new demand if cars powered by batteries no longer need catalytic converters, but nature is pointing the way on how to make hydrogen using organometallic iron compounds.
Scientists at the University of Jena have made progress in understanding how microorganisms produce hydrogen, using special enzymes called hydrogenases. Their findings were published today on the university's website.
"What is special about hydrogenases is that they generate hydrogen catalytically. Unlike electrolysis, which is usually carried out industrially using an expensive platinum catalyst, the microorganisms use organometallic iron compounds," explains Prof. Wolfgang Weigand from the Institute of Inorganic and Analytical Chemistry at the University of Jena. "As an energy source, hydrogen is naturally of great interest. That's why we want to understand exactly how this catalytic process takes place," he adds.
Hydrogenases is already used in industry. Numerous compounds have already been produced modeled on the process. In cooperation with the University of Milan, Weigand and his team in Jena have created a compound that has yielded entirely new insights into the catalysis process.
"As in nature, our model is based on a molecule that contains two iron atoms. Compared with the natural form, however, we changed the chemical environment of the iron in a specific way. To be precise, an amine was replaced by a phosphine oxide with similar chemical properties. We therefore brought the element phosphorus into play," Weigand says.
"Our goal was to understand how these protons form hydrogen. However, the proton donor in our experiments was not water, but an acid. We observed that the proton of the acid is transferred to the phosphine oxide of our compound, followed by a proton release to one of the iron atoms. A similar process would also be found in the natural variant of the molecule."
The scientists said that the process could eventually be tied to solar energy and lower the cost of producing hydrogen.