A new study spearheaded by Dr. Manish Shetty has unveiled a groundbreaking approach to converting carbon dioxide (CO2) into valuable fuels and chemicals. Their exceptional discovery, published in the journal Chem Catalysis, reveals a remarkable two-step procedure. This approach initially converts CO2 and renewable hydrogen to methanol, which can be further processed into long-chain hydrocarbons. Taken to scale, this new innovative approach could significantly reduce costly and damaging environmental impacts while uplifting local economies long overdue for investment.
To Dr. Shetty, who is an assistant professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University, circularity is a key pillar in this research. His dream is to make carbon a resource—something we can harness for gain instead of allowing it to despoil our planet. The research gives evidence to the key role that specific metal oxides play in the conversion—like ceria and zirconia. These include indium oxide, zinc-zirconium oxide, and chromium oxide.
The Conversion Process
The first step of the process is the reaction of CO2 and hydrogen to form methanol. Methanol is an important intermediate ingredient and building block to the eventual production of hydrocarbons used by a myriad of domestic, industrial, and commercial applications.
During the second stage, methanol is converted into hydrocarbons with a catalytic agent called SAPO-34. This special acidic catalyst has very special acidic sites that favor the stepwise reaction needed to produce hydrocarbons, as opposed to other products, from methanol. Her research, Dr. Shetty aims to understand the migration and positional exchange of metal ions with acid sites in SAPO-34. This process is important in determining reaction direction and reaction efficiency.
“This is just one step in a larger journey,” – Dr. Manish Shetty
Dr. Shetty goes on to explain the complexity of the interactions happening within the system. His research highlights how critical it is to understand how metals are transported throughout the reaction process.
“People often think about how molecules move in these systems, but not how the metals themselves move,” – Dr. Shetty
The Role of Metal Oxides
While this surface chemistry is important for the final success of this conversion process, the selection of metal oxides is key. By choosing particular metals, researchers can control the reaction dynamics to tune production efficiencies in the desired direction. In the past, commonly accepted theory held that if you could get two reaction components closer together, the more efficient the reaction would be.
“Historically, the idea was that the closer you bring two components, the better the reaction,” – Dr. Shetty
Dr. Shetty’s findings throw a wrench in this belief. They demonstrate how tight spacing can negatively impact performance due to interference caused from crowded metal interactions.
“But we’re finding that’s not always true. Sometimes, being too close lets the metal interfere in ways that hurt performance,” – Dr. Shetty
These types of insights are critical for improving the process and realizing more control over the final products that can be made from CO2.
Implications for Sustainability
The potential impacts of Dr. Shetty’s research reach far beyond just chemical reaction efficiencies. They look at the bottom line, their effect on the environment, and more. Industries such as paper and pulp manufacturing or ethanol refineries have the ability to capture more concentrated, high-purity CO2 emissions. This clearly represents an incredible opportunity for large-scale carbon reuse.
One goal of this research is to make chemical production more economically attractive by intensifying processes. It provides users with a high, granule-level control to maximize their production capabilities.
“This research is about process intensification—making things more economical, using smaller reactors, saving on capital and operating costs,” – Dr. Shetty
That’s the kind of future he envisions, where industries can design their processes to be much more specific.
“If someone comes to us five or 10 years from now and says, ‘I want to make propane from CO2 and hydrogen,’ we want to be able to say, ‘Pick this metal, pair it with this catalyst, and here’s how to put them together,’” – Dr. Shetty