Turning carbon dioxide into opportunity

Gary Moore, associate professor in Arizona State University's School of Molecular Sciences and the Biodesign Institute’s Center for Applied Structural Discovery, and his team are researching ways to improve the conversion of industrial waste products, including greenhouse gases such as carbon dioxide, into value-added chemicals — transforming pollution into useful materials such as fuels and other chemical building blocks.

They recently published a report on polymer-based electrode coatings — thin films placed on conductive surfaces — that help organize molecular components to speed up the carbon dioxide reduction reaction, a process that uses electricity to convert carbon dioxide into other compounds. The study also explains how charged sites within the polymers enhance the reaction.

The report, published in Chemical Communications, is part of an invited contribution to a themed collection on "Pioneering Investigators" and will be featured on the journal’s cover.

“In biology, electric-potential differences arise when charged molecules are confined to one side of a membrane, resulting in an unequal distribution of ions that can cross the membrane,” explains Moore. “These potential gradients are called Gibbs-Donnan potentials and are central to neuromuscular signaling, intracellular fluid regulation in red blood cells, and biological energy transduction.”

Put simply, living cells rely on tiny electrical imbalances across membranes to power essential processes, from nerve signaling to energy production.

Moore’s team includes Lillian Hensleigh, a doctoral student and the paper’s first author; Daiki Nishiori, who recently earned a PhD in chemistry from ASU; and Ian Peterson, who recently earned his Bachelor of Science and was an undergraduate in Moore’s lab. Nishiori is also the lead author of a review article on catalysis — the science of speeding up chemical reactions — recently published in Chemical Society Reviews.

Moore adds that “Lillian’s research demonstrates how human-engineered materials can be designed to control electric-potential differences across material interfaces and yield emergent properties that are not present in the isolated components.”

In other words, by precisely arranging molecules, the team can create new behaviors that would not exist if each component functioned alone.

“It is a privilege to conduct this work at ASU, which provides access to state-of-the-art instrumentation and a vibrant community of experts,” says Hensleigh. “I am especially grateful for the mentorship of Professor Gary F. Moore and for input from my co-authors, Dr. Daiki Nishiori and Ian Peterson.”

Hensleigh adds, “Participating in this work strengthened my problem-solving, communication and resource management skills in ways that would not have been possible otherwise.”

She is also thankful for the recognition and financial support she received from the Achievement Rewards for College Scientists (ARCS) Foundation and the Paul Liddell Synthetic Chemistry Memorial Award, saying, “It is an honor to contribute to research that expands our understanding of the molecules central to Dr. Liddell’s scientific work.”

The report centers on a deceptively simple idea: Polymer-based coatings on electrodes can organize catalysts — substances that speed up chemical reactions without being consumed — with molecular precision. Rather than acting as passive supports, the polymers actively shape the chemistry around them.

Some coatings in the study used pyridyl groups that attach to the catalyst’s metal center. Others used imidazolyl groups, which are more reactive and resemble structures found in natural enzymes. When applied to electrodes, the films surround the catalysts and create controlled environments that affect how the reaction unfolds.

The team found that polymers with imidazolyl groups performed significantly better at converting carbon dioxide than those with pyridyl groups. The imidazolyl groups helped stabilize short-lived reaction steps and improved the movement of protons and electrons during the process, increasing reaction speed and producing more of the desired product. Small changes in chemical structure led to major improvements in performance.

"Participating in this research gave me valuable hands-on technical experience while strengthening my critical thinking and creativity,” says Nishiori. “I am grateful to be part of the team that continuously inspires me to apply these experiences to tackling complex challenges in my career."

Beyond improved performance, the researchers discovered something deeper: The polymer coatings behaved like synthetic membranes, creating small differences in acidity and electrical charge across the surface. These effects led to faster reactions and better control over the final products — results not seen with isolated molecules or bare electrodes.

In essence, the team is beginning to replicate through molecular design what evolution perfected in living systems.

Their findings not only advance carbon dioxide reduction research but also show how carefully designed polymers can control the movement and distribution of charged particles to mimic biological strategies. The potential applications include medical sensors that regulate their own signals, devices that more efficiently convert fuels into electricity and back again, and future materials that blur the line between synthetic and living systems.

“This work has implications for emerging bioinspired technologies involving medical sensors and the efficient interconversion of fuels and electrical power,” says Moore. “I look forward to all that Lillian and her fellow Sun Devils, Daiki and Ian, will continue to achieve at ASU and beyond.”