The struggle for a sustainable world is being fought on many fronts. Dedicated researchers in fields we might not immediately think about are working to secure our future. One such researcher is Professor Geoffrey Coates, Chemistry and Chemical Biology. His lab is addressing climate change through what they call green chemistry. Chinelo L. Onyilofor ’15, who has worked with Professor Coates for two years, describes the lab’s goal as “working on chemistry that has real-world applications for environmental sustainability.”
Onyilofor began working with the lab as a junior after taking Professor Coates’ Organic Chemistry II course in the spring of her sophomore year. “One aspect that intrigued me was the various tangible applications that require knowledge in organic chemistry,” she says. Inspired, she decided to shadow the now fifth-year graduate student Kristina M. Hugar in Coates’ lab and became a student research assistant shortly after that.
Onyilofor and Hugar work on a project developing fuel cells as alternatives to standard batteries and combustion engines. Their research is unique because they use polymers (the compound that make up most plastics), which are affordable. Polymers have the potential to be produced and used on a large scale. “Right now, fuel cells are mostly made of very expensive platinum, so they aren’t being used by very many companies. We’re hoping to change that,” says Onyilofor.
Explaining the Chemistry
Polymers are chains of units called monomers, which are organic chemical compounds. There are many ways of creating polymer fuel cells, but Onyilofor is most interested in creating alkali anion-exchange membranes that are more cost-efficient than standard fuels cells, which require expensive metals to perform. The Coates lab produces monomers to use as “backbones” for the different polymers tested as new synthetic pathways. To create the polymer, Onyilofor must first synthesize the monomer that will serve as the repeating unit for the polymer. In the end, these membranes facilitate the passage of protons and hydroxide ions within the cell, which create energy to make it run.
“Right now, fuel cells are mostly made of very expensive platinum. … We’re hoping to change that,” says Onyilofor.
To create more efficient membranes, Onyilofor synthesizes polymers with different cations (positively charged chemical compounds) and tests their stability and mechanical properties. “What we’re trying to do is mimic the environment of the fuel cell so that the polymers we create can actually be used,” said the student researcher.
After constructing different polymers, Onyilofor tests for conductivities—essentially, how well they allow for the passage of cations across their surfaces. Next she uses nuclear magnetic resonance spectroscopy, a research method that allows her to determine the properties of a compound's structure by revealing the magnetic field of its nuclei. This allows the researcher to see whether the compound she made is the one intended so that she can be sure her data are correct.
Fuel Cells, a Sustainable Option
What makes fuel cells a more sustainable option? “Not only are they more efficient at using energy than batteries and combustion engines, but their only emissions are water vapor,” says Onyilofor. This is because fuel cells are able to access energy more quickly than their alternatives, so waste less in the process. In contrast to water vapor, combustion engines emit toxic nitrates and sulfates into the atmosphere.
The Coates lab is invested in having their completed research used toward the mass production of fuel cells. If all goes well, Onyilofor will create a series of stable compounds that can be used toward fuel cell production, including some new cationic groups. “There are so many possibilities with this work. It has the potential of lowering the CO2 emissions produced by combustion engines, which will slow climate change. And people wouldn’t have to worry about paying quite so much at the pump!”