From Carbon Dioxide to Methanol

Researchers at the University of Michigan have developed a catalyst known as cobalt phthalocyanine that converts carbon dioxide—a significant driver of climate change—into renewable fuels such as methanol.

Published in the journal ACS Catalysis, U-M researchers studied using cobalt phthalocyanine as a catalyst to convert carbon dioxide into methanol through multiple reaction steps. The first step converts carbon dioxide (CO₂) into carbon monoxide (CO) and the second step converts the CO into methanol.

This approach presents a sustainable method for reducing greenhouse gas emissions while offering an avenue to produce clean energy.

Scientists have long tried to find a way to convert CO2 into fuels like methanol chemically. Methanol could potentially be used to power vehicles in a more environmentally friendly way.

While the conversion of CO₂ to methanol has been industrialized, achieving this transformation on a large scale through electrochemical processes has proven to be a significant challenge.

“Our approach is unique because we can bring and bridge all this knowledge that each field has on the same problem. We have scientists and engineers all within one team, brainstorming and gathering insights to design and understand the system in the best way possible,” said co-primary author Kevin Rivera-Cruz, who recently received a doctorate in chemistry from U-M.e g advanced computational modeling, the researchers calculated that cobalt phthalocyanine binds CO₂ over three times more tightly than it binds carbon monoxide. They also confirmed this through experiments measuring reaction rates when varying the amounts of CO₂ and CO.

The researchers showed that the difference in binding affinity has to do with how the catalyst’s electrons interact with the CO₂ and CO molecules. To solve this issue, the researchers suggest redesigning the cobalt phthalocyanine catalyst to strengthen how it interacts with CO and lessen how strongly it binds to CO₂.

Resolving this roadblock could pave the way for using catalysts like cobalt phthalocyanine to efficiently convert CO₂ waste into methanol fuel on a large scale.

More information: Libo Yao et al, Electrochemical CO₂ Reduction to Methanol by Cobalt Phthalocyanine: Quantifying CO₂ and CO Binding Strengths and Their Influence on Methanol Production, ACS Catalysis (2023).