A Catalyst to Convert CO2 to Fuel
Carbon dioxide is the result of burning fuel to make things like cars work. Plants slowly convert that CO2 back to something organic to begin the process again. Working in his lab in the University of Delaware's Department of Chemistry and Biochemistry, Joel Rosenthal and doctoral student John DiMeglio have developed an inexpensive catalyst that uses the electricity generated from solar energy to convert carbon dioxide, a major greenhouse gas, into synthetic fuels in a far faster manner for powering cars, homes and businesses.
Gold and silver represent the gold standard in the world of electrocatalysts for conversion of carbon dioxide to carbon monoxide. But Rosenthal and his research team have pioneered the development of a much cheaper alternative to these pricey, precious metals. It’s bismuth, a silvery metal with a pink hue that’s a key ingredient in Pepto-Bismol, the famous pink elixir for settling an upset stomach.
Bismuth is a brittle metal with a white, silver-pink hue, often occurring in its native form, with an iridescent oxide tarnish showing many colors from yellow to blue. The spiral, stair-stepped structure of bismuth crystals is the result of a higher growth rate around the outside edges than on the inside edges. The variations in the thickness of the oxide layer that forms on the surface of the crystal causes different wavelengths of light to interfere upon reflection, thus displaying a rainbow of colors.
Moreover, Rosenthal says his UD-patented catalyst offers other important advantages: selectivity and efficiency in converting carbon dioxide to fuel.
"Most catalysts do not selectively make one compound when combined with carbon dioxide — they make a whole slew," Rosenthal explains. "Our goal was to develop a catalyst that was extremely selective in producing carbon monoxide and to power the reaction using solar energy."
Carbon monoxide is used industrially in the water-gas shift reaction to make hydrogen gas. It also is a prime feedstock for the Fischer-Tropsch process, which allows for the production of synthetic petroleum, gasoline and diesel.
Rosenthal says that if carbon dioxide emissions become taxed in the future due to continuing concerns about global warming, his solar-driven catalyst for making synthetic fuel will compete even better economically with fossil fuels.
"This catalyst is a critically important linchpin," Rosenthal says. "Using solar energy to drive the production of liquid fuels such as gasoline from CO2 is one of the holy grails in renewable energy research. In order to do this on a practical scale, inexpensive catalysts that can convert carbon dioxide to energy-rich compounds are needed. Our discovery is important in this regard, and demonstrates that development of new catalysts and materials can solve this problem. Chemists have a big role to play in this area."
"With this advance, there are at least a dozen things we need to follow up on," Rosenthal notes. "One successful study usually leads to more questions and possibilities, not final answers."
Chemical Plant image via Shutterstock.
For further information see New Catalyst.