Scientists have found a way turn a menacing greenhouse gas into something not often thought of as environmentally friendly—plastic.
Using copper as a catalyst and an electrical current, researchers from the University of Toronto triggered carbon dioxide to form a key ingredient used in plastics, called ethylene, by pinpointing the most efficient conditions and chemical reactions needed. Copper is somewhat of a "magic metal," according to the first author of the study and PhD candidate at University of Toronto, Phil De Luna. Copper can help create various kinds of materials including methane, ethylene and ethanol. But, it is difficult to control the conditions in order to optimize the reaction to make one product alone.
Researchers in the field are currently obsessed with copper and finding methods to perfect its use, according to De Luna. This study revealed a way to use copper as a catalyst to create ethylene while simultaneously keeping the production of another greenhouse gas, methane, to almost nothing.
"That's the most difficult challenge in this field," De Luna told Newsweek. For this study, published Tuesday in Nature Catalysis, one-of-a-kind technological equipment located at the Canadian Light Source, a research institute in Saskatoon, Canada, allowed the researchers to directly observe the chemical reactions and find the most efficient way of catalyzing the reaction to create plastics from carbon dioxide. The equipment, however, is very fragile and includes extremely high-powered and precise X-ray technology. De Luna and co-author Rafael Quintero-Bermudez worked one evening until 4 a.m. to make the process work just right and take the necessary X-ray measurements—nearly calling it quits.
"We were about to give up," Quintero-Bermudez said in a statement, "but when the results came in, they were so good we had to sit down. Really beautiful results."
It was a "spectacular moment," De Luna added.
The technique that allowed these first-time observations to happen was developed by Canadian Light Source's senior scientist Tom Regier. The specific technology allows researchers to observe the chemical reactions directly, but it's not just a visual observation like you might imagine under a microscope. Rather, it allowed them to understand and observe the chemistry, itself. Using the equipment for the study came at the perfect moment—De Luna called it "serendipitous." The lab equipment was going to be shut down for maintenance for several months just after their research was completed.
The research, however, has some caveats.
Using electricity to convert carbon dioxide into plastics requires energy "from a carbon-emitting source [such as coal, oil or a natural gas plant]," according to Taylor Weiss, senior sustainability scientist at Arizona State University who was not involved with the study. "Due to unavoidable inefficiencies, you will always emit more [carbon dioxide] producing the electricity that you will capture making ethylene." If the electricity were supplied by wind, solar, or nuclear, Weiss told Newsweek, that issue could be solved.
Weiss noted that "the research is certainly an important milestone, but if the ethylene is used to create non-biodegradable plastic, that product will still need the backing of appropriate disposal infrastructure to minimize environmental damage." In short, the plastic can't end up causing more pollution by, for instance, ending up in the oceans, rather than a landfill or being recycled and reused.
The overarching motivation behind De Luna's study is finding a way to make carbon dioxide useful without further harming the environment. This method could ideally be used in coordination with carbon sequestration, a technique that traps carbon dioxide from the atmosphere. But, what to do with the captured carbon dioxide after the fact remains a complex question.
"Can we use the [carbon dioxide], not as a waste, but turn it into a value?" said De Luna. For De Luna, the future of carbon dioxide recycling is one solution for the medium-term that can complement reducing carbon emissions. He sees a future that's filled with technologies that make something valuable from waste.
