In a recent article published in the Journal of Materials Chemistry A, Urbino described how the use of a synthetic material, called a Metal-Organic Framework (MOF), is able to break down carbon dioxide into harmless organic materials. Like plant-base photosynthesis, the process converts the compound molecule into oxygen. Instead of producing food like a plant, however, it produces solar fuel.
“This work is a breakthrough,” said UCF Assistant Professor Fernando Uribe-Romo. “Tailoring materials that will absorb a specific color of light is very difficult from the scientific point of view, but from the societal point of view we are contributing to the development of a technology that can help reduce greenhouse gases.”
Scientists around the world have been pursuing synthetic photosynthesis for years, but until recently, had not found an economical way to get visible light to trigger the chemical transformation of CO2. Ultraviolet rays can trigger such a reaction in more common materials like titanium dioxide, but UVs account for only about 3-5 percent of the light Earth receives from the sun. On the other hand, violet to red wavelengths (the visible range of sunlight), are the most common, but there are few materials capable of using these light colors to create the chemical reaction that transforms CO2 into fuel. Complicating matters, these materials tend to be rare and expensive, like platinum, rhenium and iridium. This precludes them from being economically scalable.
Uribe-Romo successfully used common and nontoxic titanium as the ‘trigger’ metal by added organic molecules that act as light-harvesting ‘antennae’. These molecules, called N-alkyl-2-aminoterephthalates, can be manipulated to absorb specific colors of light when incorporated in the MOF.
Targeting his ‘antenna’ to absorb the color blue, Uribe-Romo’s team created a blue LED photoreactor chamber capable of feeding measured amounts of CO2. LED lights surrounding the chamber’s inner surface mimicked the sun’s blue wavelength. The titanium/antenna combination was a success, causing the
chemical reaction which converted the CO2 into two reduced forms of carbon, formate and formamides (two kinds of solar fuel), all while cleaning the air.
Uribe-Romo plans to continue his research, in hopes of finding other wavelengths that might be even more efficient in capturing accumulated carbon dioxide in our atmosphere. Co2 is known as a primary driver of global warming. Reducing it while converting the compound into useful fuel could be a boon for both the health of our planet, and for supplying humanity with the energy it needs to run modern civilization.
The chemistry team at UCF is hopeful for the prospects of synthetic photosynthesis. “The idea would be to set up stations that capture large amounts of CO2, like next to a power plant. The gas would be sucked into the station, go through the process and recycle the greenhouse gases while producing energy that would be put back into the power plant.”
While the technology and infrastructure necessary to support such a vision may be years off, Uribe-Romo’s recent success at artificial photosynthesis is promising. In the future, we may see homeowners with rooftop shingles made of these materials, producing not only energy for their home, but clean air for their neighborhood. May that future come soon!
For further information on the artificial photosynthesis process, check out Professor Uribe-Romo’s YouTube video