Scientists Explore Innovative Ways to Convert CO2 into Clean Energy
As policymakers and environmental advocates gather to celebrate National Clean Energy Week, the scientific community is actively exploring innovative methods for generating sustainable energy. Among these efforts is a groundbreaking approach: transforming carbon dioxide (CO2), one of the most notorious greenhouse gases, into a viable energy source.
At William & Mary, Professor William McNamara, an inorganic chemist, is leading research that aims to mimic natural processes to facilitate this transformation. His work reflects a broader commitment by the university, which is currently observing the Year of the Environment, a yearlong initiative to enhance sustainability practices on campus and extend its influence globally.
Imitating Nature to Harness Energy
Professor McNamara’s research delves into the concept of artificial photosynthesis. This process aims to replicate how plants convert sunlight into energy. “I’ve always been fascinated by how we can harness the energy of the sun to power processes on Earth,” McNamara said. He explained that while solar power has made significant advancements, there are still numerous avenues to explore.
His previous studies focused on splitting water (H2O) to create hydrogen fuel, a reaction similar to initial steps in photosynthesis. Recently, McNamara has shifted his focus to the later stages of this process, investigating how plants convert CO2 into glucose, the primary energy source for plants. By studying these natural mechanisms, he hopes to develop a method for converting CO2 into fuels that can be utilized by human engines.
In this endeavor, McNamara emphasizes the importance of catalysts—substances that accelerate chemical reactions. His team is modeling their catalysts after an enzyme found in plants known as carbon monoxide dehydrogenase (CODH). This enzyme plays a crucial role in converting carbon monoxide to CO2 and vice versa. “The types of catalysts we’re working on are modeled off of CODH,” McNamara explained, noting that key metals, particularly iron and nickel, are integral to this catalytic process.
Advancing Sustainable Solutions
McNamara’s focus on iron and nickel is intentional, as these metals are not only abundant but also cost-effective compared to rarer alternatives like ruthenium and iridium. His team aims to establish a CO2 conversion method that can be scaled up for broader use, making it economically viable.
The catalysts developed in McNamara’s lab incorporate ligands—molecules that bind to metals—creating a coordination complex essential for the reaction. He likens this to the way mammals breathe, where oxygen binds to hemoglobin, a metal-ligand complex. “By making specific ligands, we can regulate the reactivity of that metal center,” he noted.
The current focus of McNamara’s research involves reducing CO2 to produce compounds such as carbon monoxide or formate, which can be further processed into fuels like methane, the main component of natural gas. With a dedicated team of 11 undergraduate researchers, McNamara’s lab has already produced several successful catalysts.
“Our next steps are to understand what the specific products of this reaction are and how much of them are out there,” he said. This research will provide insights into the catalysts’ selectivity and the overall mechanism, laying the groundwork for accessing larger hydrocarbon molecules in the future.
McNamara highlights the renewable aspect of using CO2 as a fuel source. “The advantage with this technique is that our initial fuel input would be CO2, not some non-renewable gas pumped from below the Earth’s surface,” he explained. This approach aims to recycle carbon already present in the atmosphere, rather than introducing new carbon emissions.
While the prospects for fuel conversion are promising, McNamara acknowledges the challenges that remain in making CO2 a practical fuel source. He pointed out the need for solutions regarding reaction scalability, catalyst stability over time, and the storage and transportation of reactive species.
“The problem demands a very multidisciplinary approach,” he noted, reflecting on the collaborative efforts of specialists in materials science, engineering, and inorganic chemistry working towards this goal. Each project contributes to the broader mission of achieving a cleaner future.
Students involved in McNamara’s research express their enthusiasm for the work. Yuanheng Zhuang, a sophomore who joined the lab, shared, “I’m learning to think like a researcher, use ingenuity to overcome problems and work efficiently in the lab. Gaining those skills while working on a project I’m passionate about is a unique opportunity.”
As scientists like McNamara continue to push the boundaries of energy innovation, the potential for CO2-derived fuels and other applications could have a significant impact on sustainability efforts worldwide.
