It may be that some choose to ignore the signs of global climate change for now. The effects, however, of the far-reaching consequences of that change are slowly becoming unavoidable. Rising sea levels, unpredictable and violent weather patterns, mass extinctions and rising levels of lung disease from air pollution are all part of a toxic mess that humans have created for themselves.
So what can we do to try and work our way out of this mess? Scientists are feverishly at work trying to answer that question.
One new innovation that is making its way through labs in places like the University of Illinois at Chicago is the idea of artificial leaves. Researchers at the university have designed a leaf that, if introduced into our environment, would help clean our air from the carbon dioxide that is so clearly responsible for many of our problems.
What Is an “Artificial Leaf,” Exactly?
An artificial leaf is just that: a leaf made in a laboratory to mimic the photosynthesis that organic leaves use to fix carbon dioxide (cleaning the air) and produce oxygen.
The idea was pioneered by Professor Daniel Nocera and Professor Pamela Silver, a specialist in energy science at Harvard University. In 2016, Nocera and Silver designed a “leaf” using a “hybrid approach” of inorganic chemistry and biology. In photos, Silver and Nocera’s “leaf” looks like a small, very flat teabag or a piece of paper trapped between laboratory slides. Functionally, it is a plate designed to absorb light coated in catalysts that convert carbon dioxide to carbon monoxide.
Nocera and Silvers’ work was successful in having their “leaf” make liquid fuel from sunlight, carbon dioxide and water (just like a real leaf). Their leaf worked at an efficiency level of about 10 percent, with one-tenth of the energy in sunlight converted into fuel. (In comparison, natural leaves only convert about 1 percent of solar energy into carbohydrate fuel.)
After this breakthrough, scientists in labs around the world started working on their own versions of artificial leaves.
What Innovations Did Illinois-Chicago Add?
At U. of Illinois-Chicago, Assistant Professor Meenesh Singh and his graduate student Aditya Prajapati succeeded in making a leaf that would actually survive in the outside environment.
“So far, all designs for artificial leaves that have been tested in the lab use carbon dioxide from pressurized tanks,” Singh explained in February of 2019. In order for this plan to work in the real world, a leaf had to be designed that would be able to grab carbon dioxide from a much wider range of sources, such as the air or the emissions from factories and coal-fired plants.
Singh and Prajapati solved this problem by encapsulating the traditional artificial leaf design in a capsule made of semi-permeable ammonium resin filled with water. The way this now works is that water inside the membrane evaporates out when warmed by sunlight. As the water evaporates and passes through the membrane, it then pulls carbon dioxide from the air.
This is a breakthrough that foreshadows the ability to use the leaves in everyday environments. The design, again according to Singh, uses “readily available materials and technology that, when combined, can produce an artificial leaf that is ready to be deployed outside the lab where it can play a significant role in reducing greenhouse gases.”
According to Singh and Prajapati’s calculations, 360 “leaves,” each 1.7 meters long and 0.2 meters wide, would produce nearly half a ton of carbon monoxide per day. That CO could then be used to create synthetic fuels.
In addition, the same array of “leaves” covering 500 meters could reduce carbon dioxide levels by 10 percent in the surrounding area. Within 100 meters of the array, that carbon dioxide level would drop in one day.
What Could the Future Hold?
If this science continues to progress, we might one day see power plants surrounded by poles and scaffolding full of artificial leaves, each trapping the carbon dioxide produced by a power plant and converting it to usable fuel and breathable oxygen.
Will this come too late to reverse our climate crisis? We don’t know yet. All we can do is keep working for change and supporting climate scientists as they seek solutions.