A catalyst promotes a chemical reaction without being changed by it. Most conventional cars and trucks today use catalytic converters to break down exhaust emissions like carbon dioxide. Catalysts are used to split water into its component parts, yielding hydrogen as a byproduct, and for making methanol, an important feed stock for many forms of plastic, from carbon dioxide. The problem with many catalysts is they require significant amounts of rare metals such as ruthenium, osmium, and iridium. Known as “noble metals,” they are expensive to mine and refine in commercially useful quantities.
In a report published in the journal Science on November 29, scientists at Lund University, in collaboration with researchers at Uppsala University and the University of Copenhagen, report they have created new molecules based on iron, which is cheap and abundant, that can perform the same catalytic functions as the noble metals at significantly reduced cost.
“Our results now show that by using advanced molecule design, it is possible to replace the rare metals with iron, which is common in the Earth’s crust and therefore cheap,” says Chemistry Professor Kenneth Wärnmark of Lund University. “The good result depends on the fact that we have optimized the molecular structure around the iron atom,” explains his colleague Petter Persson.
According to Science Daily, the optimized iron molecule could be used in new types of photocatalysts for the production of solar fuel — either as hydrogen through water splitting or as methanol from carbon dioxide. The new research may also lead to another application for iron molecules — light emitting diodes. The light created so far is faint, but when LEDs were first invented, people scoffed at the pitifully small amount of light they produced. No one is scoffing today.
Scientists see the world in different terms than most people. They know basic research requires a lot of time to yield favorable results. “We believed it would take at least ten years,” says Kenneth Wärnmark. He and his team are delighted it took half that time.
Cheaper catalysts could be a boon to quest to provide plastics not sourced from petroleum and hydrogen for transportation applications that do not lend themselves to battery electric solutions, such as ocean-going cargo ships and long range airplanes. Any advances that can turn carbon dioxide into useful products or lower the amount of emissions entering the atmosphere are welcome news to us all.