Illuminating CO₂ Conversion Mechanisms: 2022 YPS Grant Project Insight

YPS Grant Project Insights offer short, digestible explanations of the diverse initiatives funded since the program launched in 2022. 

As the need for renewable energy sources becomes more urgent, scientists are exploring ways to turn carbon dioxide (CO₂) into liquid fuels, such as methanol. However, conventional methods for this transformation remain inefficient.

Supported by a Yale Planetary Solutions grant, Eric Altman, Roberto C. Goizueta Professor of Chemical & Environmental Engineering & of Materials Science, and collaborators Udo Schwarz of the Department of Mechanical Engineering and Hailiang of the Department of Chemistry have made progress toward a more efficient pathway for converting this greenhouse gas into methanol. Their 2022 project was titled “Atomically Resolved Single Molecule Microscopy of Catalytic Intermediates in CO2 Reduction.”

One promising approach developed by researchers at Yale uses a catalyst called cobalt phthalocyanine (CoPc), which produces carbon monoxide (CO) in an intermediate reaction step. 

For the reaction to proceed efficiently, CO must bind to the catalyst just strongly enough, neither too tightly nor too weakly. Achieving this balance has been a challenge, and conventional analytical methods have not been precise enough to show how CO interacts at the level of individual molecules.

To gain better insights, the team developed a new imaging and analysis method using advanced scanning probe microscopy. Using a silver surface, they found that the CoPc molecules sit in a slightly tilted, asymmetric position. Surprisingly, the imaging reveals that CO does not bind most strongly directly above the central cobalt atom, but instead, off to one side.

By demonstrating remarkable precision in measuring forces and energies at this miniscule scale, these findings both deepen scientists’ understanding of molecular interactions and offer new possibilities for designing more effective synthetic pathways.

Once methanol synthesis from CO₂ and hydrogen has been optimized and is driven by renewable energy, methanol can be used directly as a fuels or easily converted to dimethyl ether, a diesel substitute. Existing technologies could further process it into gasoline or kerosene, which could be especially important for industries like aviation and shipping, where switching to electricity poses significant challenges. Replacing fossil fuels in these sectors with renewable, CO₂-derived fuels could reduce global carbon emissions by an estimated 5–10%. 

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