Research conducted in the Flex Lab at the Institute for Sustainability and Energy at Northwestern (ISEN) is solving for two global crises—increasing carbon dioxide emissions and diminishing fossil fuel reserves. Yijin Kang, visiting professor with the International Institute for Nanotechnology at Northwestern (IIN), believes a remedy for the behemoth challenges is in the field of energy conversion and storage. His research and findings were published this week in Nature Catalysis.
The Challenge
Carbon dioxide emissions are the waste product of industrial chemical processes used to make plastics, rubber, gasoline and other materials common to our daily lives. Carbon dioxide is also the most pervasive greenhouse gas in our atmosphere, accelerating climate change.
Fossil fuels, such as oil, contain carbon and are often the base material used in these facilities. Fossil fuels are non-renewable natural resources—our supply is limited and growing smaller each day. It is widely believed that we will soon run out.
The Solution
Together with his on-site research team of doctoral students and postdoctoral researchers from his home institution—the University of Electronic Science and Technology of China—Kang discovered a catalyst to convert single carbon compounds, like carbon dioxide and carbon monoxide, into multi-carbon compounds, such as acetate. His technique produces a product that is 50 percent selective for acetate as the desired chemical output, as compared to previous techniques that yielded a 20 percent level of selectivity—where the majority of the resulting product was a complex mixture that requires further costly separation. Thanks to Kang, for the first time, the technique is now well enough refined to appeal to industry.
In Kang’s method, a jolt of electricity is delivered via copper nanosheets as the catalyst for the transition. This approach offers alternatives to replace carbon fossil fuels as a feedstock for the production of plastic, rubber, and fuel. At the same time, the process can prevent greenhouse gas, including carbon dioxide, from reaching the atmosphere.
Without catalysis, these reactions would not naturally occur. “We do the conversions between the electricity and the chemicals,” explains Kang. “All of those processes involve what we call catalysis, or catalytic processes. That’s the core of our research.”
“We do the conversions between the electricity and the chemicals. All of those processes involved what we call catalysis, or catalytic processes. That's the core of our research." — Yijin Kang
Flash Forward
Catalysis has long been a key component of the chemical industry, and according to Kang, will continue to be in the future.
When it comes to fuel production, Kang believes we will transition to an energy system that does not begin with carbon-based fossil fuels, but rather, relies on a catalyst to split water molecules into hydrogen and oxygen. The resulting hydrogen is a promising technology for the storage of energy from renewable sources, like solar and wind, in the form of fuel cells, where it can be drawn from as needed to power vehicles, for example.
According to Kang, it will be even more important at that time to be able to generate multi-carbon compounds like acetate in order to produce the materials we have come to rely on daily but that will be missing in the carbon-free “hydrogen economy.” His technique will work with single carbon compounds including carbon dioxide in addition to carbon monoxide, a naturally abundant gas in the atmosphere, and could play a vital role in the production of materials such as plastics and rubber.
“Both batteries and fuel cells store energy in the form of chemicals. But when you really need to use them you can convert them back to electricity. So that is the core science our group is working on. We do the conversions between electricity and the chemicals,” says Kang. “In this way you convert a small molecule into the feedstock of our life.”