Building a Synthetic World from Thin Air

As the world begins taking small steps to move away from its dependence on fossil fuels, researchers are increasingly looking for creative solutions to manufacturing the materials that make modern life possible.

After Karthish Manthiram completed his postdoctoral studies at Caltech in 2016, he built a laboratory at the Massachusetts Institute of Technology that advances the science needed to reduce the carbon footprint of the chemicals and materials that make up the physical world. His work harnesses sustainable energy sources, like wind and solar, to synthesize plastics, fertilizers, and other manmade materials from nitrogen, water, and carbon dioxide, providing an alternative to fossil fuels.

He has now returned to Caltech as a professor of chemical engineering and chemistry.

Why did you decide to become a chemical engineer and chemist?

The thing that made chemistry and chemical engineering really attractive to me as a combined discipline is that it's able to describe processes across a wide range of scales. You can go from microscopic phenomena, including understanding of how bonds in molecules form and break, all the way up to macroscopic phenomena, like how a large-scale chemical plant works.

As a kid, I was obsessed with electricity—I thought it was magical. I would sit on the floor of my childhood bedroom putting together whatever components I could find—wire, batteries, and light bulbs I had salvaged. It was a very empirical process—discovering what arrangements made a lightbulb glow bright, and which ones didn't work. This early interest in electricity gave way to an even more diverse set of interests in robotics and chemistry as I went into high school and college. Now, many of these interests have come together as my group is using electricity to make and break chemical bonds, using our perspective spanning chemistry and chemical engineering.

Can you describe your work for us?

If we asked people to identity where they generate a carbon footprint in their own life, they might point to the action of driving their car, knowing it runs on gasoline, or the action of turning on a light switch, knowing that it is likely powered by fossil fuels. They often don't realize that there is a carbon footprint behind virtually everything they interact with. There's a carbon footprint behind the plastic bottle containing the hand sanitizer I use. There's a carbon footprint behind the laptop I'm speaking through right now. There's a carbon footprint behind the clothes I'm wearing. It's inescapable. Specifically, this carbon footprint is an emission of carbon dioxide or another greenhouse gas that contributes toward global warming, as part of the processes used to make the chemicals and materials that go into manufacturing the physical world.

Our group is focused on trying to convert air, water, and renewable electricity into useful chemicals, providing a means of decarbonizing chemical and material manufacturing. Modular, distributed devices powered by solar and wind could be the chemical factories of the future.

How does sustainability play into your work?

Diverse activities are going on in the broader community to electrify particular steps of chemical synthesis. Our group is specifically trying to create a synthetic toolkit that allows us to conduct the difficult steps that are underexplored and underdeveloped.

As an example, we are trying to develop methods to convert nitrogen and water into ammonia at room temperature; ammonia [a compound of nitrogen and hydrogen] is important because it's used as a fertilizer. It turns out it is really hard to do that because the bond in nitrogen is really strong and unreactive, but our group has found a way to do that at the highest rates reported at ambient conditions.

We can also consider how this interfaces with other efforts at Caltech. If someone is making solar power from the sun, that energy can be stored in a battery. [Assistant Professor of Chemistry] Kim See's group is working on that. Our group is looking for ways to create materials using that energy. I think a lot of these technologies being developed at Caltech will fit together, and I think that's really exciting.

What's the most challenging thing about this kind of science?

The hardest part of this is learning how to facilitate the molecular-level dance that occurs between molecules on the surface of a catalyst. A catalyst's job is to break specific bonds and form specific bonds. We are working to design catalysts that harness electric fields to drive bond breaking and forming steps that are needed for sustainable chemical synthesis.

What does a typical day look like in your lab?

A lot of movies show a scientist working alone in a basement and coming up with an idea on their own; it turns out that science is done in a very collaborative and social fashion. One of the things we really value in our group is that we advance the science needed for many of our discoveries through Socratic dialog, which is discovery guided through questions. It's one of my favorite parts of my day: spending time with my students sketching through ideas and data at a whiteboard, and asking questions that enable them to have an "Aha!" moment.

There's also a lot of failure in science on a given day. A lot of the things we try don't work because they're so challenging, but they're interspersed by these moments where the creativity and perseverance of our team members result in an important and enabling discovery.

How do you like to spend your free time?

I have loved running and long walks since I was a kid, and it is one of my favorite ways to spend time with friends and family. I have also always enjoyed capturing people and the world around me through photography and videography; recently, I have gotten more into taking portraits. There is a certain thrill to figuring out how to mold the present setting and manipulate the lighting to make it an aesthetically pleasing canvas for a portrait.