CO2 to Methanol Conversion for Renewable Fuels

Research done by a team at the University of Michigan has developed a catalyst material known as cobalt phthalocyanine that converts carbon dioxide (a compound that boosts climate change) into a renewable fuel, methanol.

This research, published in the journal ACS Catalysis, is studying cobalt phthalocyanine as a catalyst in order to convert carbon dioxide into methanol through multiple reaction steps.

The reaction includes converting carbon dioxide (CO2) into carbon monoxide (CO). The second reaction is converting carbon monoxide (CO) into methanol.

Actually, the conversion of CO2 to methanol has been industrialized, but achieving this conversion on a large scale is a hard challenge.

Co-primary author Kevin Rivera-Cruz, who recently received a doctorate in chemistry from the University of Michigan, said, “Our approach is unique because we are able to 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”.

Source : DOI: 10.1021/acscatal.3c04957

The newly developed catalyst material (cobalt phthalocyanine) acts like a molecular hook for CO2 and CO molecules. The arrangement of CO2 and CO molecules around the cobalt phthalocyanine is important to highlight because the arrangement determines the strength of each gas molecule’s binding. The problem that they found is that cobalt phthalocyanine is binding much stronger with CO2 compared to CO. This results in difficulties, such as the fact that the fact that once CO is produced in the first step, it is displaced by another CO2 molecule before it can be further converted to methanol.

The team did advanced computational modeling and found that cobalt phthalocyanine is binding with CO2 over three times stronger than its binding strength with CO. This computation was also proved by an experiment measuring the reaction rate when varying the amounts of CO2 and CO.

The variation in binding power between cobalt phthalocyanine and molecules has to do with how the catalyst’s electrons interact with the CO2 and CO molecules. To solve the problem mentioned earlier, the team is proposing to redesign the cobalt phthalocyanine to improve how it interacts with CO and decrease the binding reaction with CO2.

By solving this issue, this finding could be very useful in creating a large-scale CO2 to methanol conversion facility to help solve the climate change issue.

Source : 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). DOI: 10.1021/acscatal.3c04957