Yale researchers are leading the way in developing a new generation of liquid fuels activated by sunlight. This initiative could transform the way we produce energy while reducing CO2 emissions.
A new hybrid methodology
Over the past decade, fundamental research aimed at creating sustainable solar-powered liquid fuels has reached a turning point. New semiconductor materials can efficiently capture sunlight and catalyze the conversion of carbon dioxide into valuable products, such as liquid fuels.
However, it is often difficult to design a unique product. Molecular catalysts can produce a single product from CO2, but their stability remains a challenge. Therefore, many scientists believe that none of these approaches are adequate for large-scale production.
Now a third methodology is emerging. Yale chemists involved in the Center for Hybrid Approaches to Solar Energy (HUNT), combine new semiconductor materials with new molecular catalysts to create more powerful, more modern processes, potentially scalable for wider use.
This innovative approach, described in two recent studies, represents a combination of the best features of both worlds, according to the researchers. This could lead to alternative fuels with the added benefit of removing CO2 from the air.
“ These two articles give me a lot of hope that a hybrid approach can work said Eleanor Stewart-Jones, a graduate student in the Department of Chemistry Yale and co-author of one of the studies. “We’re definitely finding new ways to improve or increase responsiveness. »
Inter-institutional cooperation
About a dozen Yale faculty members and graduate students are part of CHASE, a federally funded solar energy research center comprised of six US research institutions, based at the University of North Carolina at Chapel Hill.
CHASE’s mission is to accelerate research that can lead to the production of liquid fuels from sunlight, water, nitrogen and carbon dioxide.
Yale researchers include Nilay Hazari, the John Randolph Huffman Professor of Chemistry; James Mayer, Charlotte Fitch Roberts Professor of Chemistry; and Hailiang Wang, professor of chemistry, all from the College of Arts and Sciences.
“ It is inspiring to see the dedication that our students, postdoctoral fellows and colleagues at partner institutions put into this work Hailiang Wang said. ” Each new discovery brings us closer to developing the technology needed for practical solar fuels. »
The genius of the Yale research is highlighted in two new CHASE studies, both published in the Journal of the American Chemical Society. They focus on silicon-based photoelectrodes, solar battery components that capture sunlight and convert it into electricity.
Innovative electrodes
in the first studyled by Hailiang Wang’s lab at Yale and Tianquan Lian’s lab at Emory University, researchers constructed an electrode composed of an array of silicon micropillars coated with a layer of superhydrophobic fluorinated carbon.
This strategy increased the total surface area of the electrode and led to a dramatic increase in catalytic activity. “ We observed a significant increase, up to 17 times higher catalytic activity than the previous record for silicon photoelectrodes said Bo Shang, a graduate student in chemistry at Yale and co-author of the study.
The approach enabled the most efficient photoelectrocatalytic conversion of CO2 to methanol ever reported from silicon. Methanol is a colorless alternative liquid fuel.
For another study, Mayer and Hazari’s labs at Yale collaborated on a process that involves thin wafers of porous silicon, a form of silicon etched with channels called nanopores. The researchers attached a rhenium molecular catalyst to these electrode pads.
“ To our knowledge, this is the first time anyone has attached a molecular catalyst to porous silicon said Stewart-Jones, a graduate student in Mayer’s lab and co-author of the study.
Improved chemical reactions
There chemical reaction The resulting reaction, fueled by sunlight, converts CO2 to carbon monoxide more consistently and reproducibly than when molecular catalysts are combined with flat, non-porous silicon.
“ We have successfully immobilized an efficient molecular catalyst for CO2 reduction on a silicon material that absorbs sunlight ” said Xiaofan Jia, a postdoctoral fellow in Hazari’s lab and another of the study’s first authors. ” This allows the device to directly use the sun’s energy to produce fuel. »
Together, the two studies highlight the diversity and creativity of the CHASE project, Wang added.
“ These two works develop photoelectrodes for CO2 reduction with silicon and a molecular catalyst, but use very different approaches Hailiang Wang concluded.
Description: Illustration by Michael S. Helfenbein