Author: Jonathan Deutschman

Today’s electric vehicles are a good example of renewable energy that mitigates carbon dioxide emissions. But what if that same energy could actively combat it?

Yayaun Liu, assistant professor in the Department of Chemical and Biomolecular Engineering, is leading a team that is exploring that idea.

“We are trying to develop new carbon dioxide capture mechanisms that can be driven solely by renewable electricity, which can operate at ambient conditions, potentially be more energy-efficient, and can be deployed at plug-and-play units to accommodate the multi-scale nature of carbon capture needs,” said Liu, whose team’s study was published October 13 in Nature Energy.

The paper, which examines alternatives to the conventional approaches to carbon dioxide separation strategies, proposes a less-intrusive and more eco-friendly process powered mainly by electrochemical means.

Emissions from carbon dioxide are a leading contributor to climate change, and the current accepted approach to mitigation is essentially capturing it directly from ambient air and subsequent utilization or sequestration. This process – known as thermal amine scrubbing – employs nitrogen bases which requires substantial thermal energy input and entails corrosion of process equipment and evaporation of toxic residue into the environment. Liu, et al’s research explores a less-invasive method.

“In this paper, we discovered a library of organic molecules that can reversibly capture and release carbon dioxide upon electrochemical stimuli (reduction and oxidation cycles),” said Liu. “We fundamentally elucidated the carbon capture mechanism and established design rules for precise molecular tuning so that they can possess desirable properties for practical carbon capture applications.”

The ultimate goal is a system based on existing renewable electricity sources that would not require the retrofitting that current carbon dioxide removal systems typically do. Liu explained that the refuse would either become commodity chemicals or be buried underground in an approach known as carbon capture and storage. Hence the utilization/sequestration dynamic remains in tact, but the methodology preceding that would be more eco-friendly and less disruptive to existing infrastructure.

The research cited in the paper aims to significantly deepen the fundamental understanding of the development of electrochemically-mediated carbon capture technologies. Though Liu said that further engineering optimizations are needed to optimize the process, the lab work and subsequent results “demonstrated promising performance for point source carbon capture.”

The other authors on the paper are T. Alan Hatton of Massachusetts Institute of Technology and Yuanyue Liu of The University of Texas at Austin.