A new catalyst paves the way for ethanol-based fuel cells

A team of scientists from the US Department of Energy, in collaboration with researchers from the University of Delaware and the "Yeshiva University" institute, has developed an innovative catalyst that will enable the application of ethanol-based fuel cells.

A team of scientists from the US Department of Energy, in collaboration with researchers from the University of Delaware and the Yeshiva University Institute, has developed a state-of-the-art catalyst that will enable the application of ethanol-based fuel cells. The highly efficient catalyst performs two essential steps needed to oxidize ethanol, which until now have been unachievable , and enables the production of clean energy in fuel cell reactions. The research findings were published online in the January issue of The scientific journal Nature Materials

Like batteries that never run out, hydrogen fuel cells convert hydrogen and oxygen into water, and as an integral part of the process - generate electricity. However, it is not easy to achieve efficient production, safe storage and transportation of hydrogen for use in fuel cells. As an alternative, scientists are looking at the inclusion of hydrogen-rich compounds, such as the use of liquid ethanol in a system known as a direct ethanol fuel cell.

"Ethanol is one of the ideal reactants for fuel cells," says chemist Radoslav Adzic. "It is easy to produce, it is non-biodegradable, non-toxic, easy to transport and has a high energy content. In addition, after only minor changes, we can use the gas storage and transportation infrastructures that already exist today."

A main obstacle to the commercial use of direct fuel cells from ethanol is the slow and inefficient oxidation of the compound, which splits it into hydrogen ions and electrons, which are required to generate electricity. In particular, scientists were unable to find a catalyst capable of breaking the chemical bonds between ethanol's carbon atoms.

However, this team of scientists managed to find it. The catalyst, which consists of platinum and rhodium atoms anchored on tin dioxide nanoparticles, is able to cleave carbon bonds at room temperature and effectively oxidize ethanol to its main product - carbon dioxide. Other catalysts, by comparison, produce acetaldehyde and acetic acid as the main products - two substances that are not suitable for energy production.

"The ability to cleave a carbon-carbon bond and obtain carbon dioxide at room temperature is a completely new property of catalysts," says the researcher. "No other catalysts exist today that are capable of achieving this with practical potentials."

The structural and electronic properties of the new catalyst were determined using powerful X-ray absorption methods, combined with information obtained from transmission electron spectroscopy (TEM) analyses. Based on these findings and additional calculations, the researchers concluded that the high efficiency of their tertiary catalyst originates from the combined activity of all three components together - platinum, rhodium and tin dioxide - information that could also be important in other energy applications.

"These findings can lead to new research possibilities, not only for electrical catalysts and fuel cells, but also for many other catalytic processes," the researcher notes. In the next step, the researchers will test the performance of the new catalyst in an actual fuel cell in order to observe its unique characteristics firsthand.

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