Oct. 27, 2021
Student-led international project develops new chemical pathway to turn carbon dioxide into useful products
Joshua Koenig鈥檚 work in catalyst design focuses on 鈥渃losing the carbon loop.鈥澛It involves converting carbon dioxide (CO2) into useful fuels and chemical feedstocks, keeping the greenhouse gas out of atmosphere.
鈥淐losing the carbon loop using CO2 conversion processes powered by renewable energy sources could be a powerful way to combat global warming caused by greenhouse gas emissions,鈥 says Koenig, a PhD student in the in the .
However, because of CO2鈥檚 properties, chemically activating the inert gas requires a lot of energy 鈥斅爀ven when using catalysts to help convert the CO2.
Now, in an international, doctoral student-led research project, Koenig was able to chemically modify a well-known organometallic catalyst so it efficiently converts CO2 into carbon monoxide using much less energy.聽Carbon monoxide is a chemical feedstock that can be used to make synthetic fuel and a variety of chemicals.
Koenig modified the organometallic catalyst (called rhenium bipyridine) by linking it to 聽an 鈥渙rganic chromophore鈥 commonly found in red paints (a chromophore is the part of a molecule responsible for its colour).
鈥淚 synthesized a new organometallic-chromophore dyad, which performed the same chemical transformation that the standard organometallic catalyst does on its own, but at a much lower applied voltage," Koenig says.聽鈥淥ur finding represents an exciting new avenue for exploring improved catalyst design.鈥
鈥淭he discovery Josh made is beautiful chemistry,鈥 says project collaborator Zachary Dubrawski, also a PhD student in the Department of Chemistry. 鈥淚t opens a new door in the molecular design field.鈥
Dubrawski analyzed the catalytic reaction that used Koenig鈥檚 modified catalyst, to determine what each of the chemical steps in the catalytic cycle looked like.
Koenig also reached out to Keerthan Rao, a PhD student in chemistry at the University of Kentucky, to construct a computational model of the catalytic reaction. This model corroborated Koenig鈥檚 experimental observations and Dubrawski鈥檚 mechanistic analysis.
鈥淥verall, this project harmoniously blended the unique expertise of three different research groups successfully into one high-impact collaboration,鈥 Koenig says.
Koenig is the lead author on the team鈥檚 , 鈥淟owing Electrocatalytic CO2 Reduction Overpotential Using N-Annulated Perylene Diimide Rhenium Bipyridine Dyads with Variable Tether Length,鈥 which is published in the Journal of the American Chemical Society.
Project required entrepreneurial approach
The project鈥檚 success required a lot of persistence, the strength of collaboration, and some entrepreneurial thinking.
Koenig, a member of the led by professor of organic chemistry Dr. Gregory Welch, PhD, made his key discovery of the modified CO2 conversion catalyst just prior to the start of the COVID-19 pandemic. The pandemic shut down the Welch lab for three months.
鈥淪o I鈥檓 sitting with this great result and there鈥檚 absolutely nothing I can do with it now,鈥 Koenig says.
That鈥檚 when he reached out to one of Welch鈥檚 chemistry colleagues, Dr. Chad Risko, PhD, at the . Risko connected one of his PhD students, Keerthan Rao, with Koenig.
Koenig also enlisted Dubrawski, a member of the led by chemistry professor Dr. Warren Piers, PhD, in the project.
The collaboration combined the Welch group鈥檚 expertise in pi-conjugated materials for organic electronics with the Piers group鈥檚 knowledge of organometallic complexes commonly used as catalysts.
Courtesy Josh Koenig
Adding Rao鈥檚 computational modelling expertise 鈥測ielded a much more robust result,鈥 Dubrawski says.
鈥淲e were able to successfully design a series of dyad systems, fully investigate their optoelectronic properties, and test their CO2 conversion abilities,鈥 Koenig says.
The team showed that the chromophore added to the organometallic catalyst acted as an 鈥渆lectron reservoir鈥 for the catalyst, thus enabling a new and highly effective catalytic CO2 conversation pathway.
鈥淭his was a student-led interdisciplinary project that tackled aspects of climate change, and has now been recognized by one of the top journals in science,鈥 says Welch.
鈥淥ne of the top goals of our team supported by Canada First Research Excellence Fund was to discover new catalyst design principles for efficient CO2 conversion,鈥 says Piers. 鈥淛osh has delivered on that promise with a key insight that will inform innovation in this area for years to come.鈥
The 鈥渞eal-world鈥 significance of the research is that there are hundreds of already-known CO2 conversion catalysts and organic chromophores, but most operate with high energy demands. The work done by Koenig and colleagues provides a straightforward way to inexpensively reduce the input energy required.
With further work, it鈥檚 possible to develop some organometallic-chromophore dyad combination that would deliver 鈥渃hampion鈥 CO2 conversion performance at an industrial scale, Koenig says.
The team鈥檚 research was funded by the , the , and the .