How unlocking ‘sticky’ chemistry may lead to better, cleaner fuels

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How unlocking 'sticky' chemistry may lead to better, cleaner fuels

Study sheds new light on carbon dioxide transformations

In a new study, chemists have developed a novel framework for determining how effectively carbon monoxide sticks to the surface of a catalyst during conversion from carbon dioxide.

This stickiness, known as carbon monoxide (CO) adsorption energy, is a property that can often decide the final product of a chemical reaction. Using a widely accessible advanced electroanalytical technique, researchers found that the strength of this energy actually relies on a mix of reaction factors, including the type of catalyst material, applied voltage, and the surface's structure.

This is a major step for the field, as gaining a better understanding of how CO adsorption works in real-time can help scientists search for innovative ways to recycle its counterpart, carbon dioxide, into useful fuel products, like methanol and ethanol. By designing better catalysts, these new insights could be used to accelerate the development of cleaner technologies that support a more sustainable future, said Zhihao Cui, lead author of the study and a postdoctoral student in chemistry at The Ohio State University.

"Our approach provides a vital bridge between theory and experiment by helping guide the design of catalysts that can convert CO₂ into useful liquid fuels more efficiently," said Cui.

The study was recently published in Nature Catalysis.

Until now, researchers lacked an experimental method to measure carbon monoxide's binding strength under real reaction conditions, meaning scientists' theoretical predictions about reaction results were limited in their ability to capture the complexities of electrocatalytic environments. Yet with this study's method, the team was able to validate their theories by viewing how carbon monoxide interacts with materials like gold and copper, insights that could guide the design of more efficient catalysts for carbon conversion.

Researchers found that while carbon monoxide can bond with gold and copper with similar strengths, only copper is capable of generating multi-carbon products from CO₂. These relatively surprising results reveal that the CO adsorption process is actually more complex than researchers previously thought, said Anne Co, co-author of the study and a professor in chemistry and biochemistry at Ohio State.

"Carbon dioxide is such a stable molecule, so it's hard to break down," said Co. "Whether it takes two or twelve steps to complete a reaction, it usually requires a lot of energy."

While chemists typically use electrochemistry to generate and store the energy needed, streamlining the process using this team's new framework could make it easier to realize the energy needs of a potential chemical reaction. Importantly, it's a significant step in designing better, more sustainable fuels, said Cui, especially since the method is simple enough not to require expensive equipment and can be easily adapted for other types of catalysts.

"Our framework enables other researchers to extend the same experiment to a wide range of catalysts," said Cui.

Researchers noted that while their method does have some limitations, next steps include plans to further refine their model and methods in order to yield more nuanced insights into the chemical world.

"Even a very simple technique such as the one we used in this study can make a really huge difference in this field," said Cui. "So as long as your idea is new, you may be able to measure something that was previously considered impossible to measure."

Other Ohio State co-authors include Kassidy Aztergo and Jiseon Hwang. The study was supported by the National Science Foundation.

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