Those doomsday greenhouse gases that are supposedly choking the atmosphere, playing havoc with the climate and otherwise scaring the hell out of us may well have met their match.
A University of Central Florida (UCF) chemist has found a way to trigger a synthetic form of photosynthesis that turns the greenhouse gas carbon dioxide into clean air – and produces clean energy.
Photosynthesis is the process by which plants capture energy from the sun, convert carbon to food and produce oxygen as a waste product.
Assistant Professor Fernando Uribe-Romo mimicked that process, but took it a step further to improve on Nature; instead of producing plant food, his game-changing experiments have produced solar energy in the form of formate and formamides which are used in fuel cells to produce electricity.
Uribe-Romo and a team of chemistry students achieved this by triggering a chemical reaction in a synthetic material called metal-organic frameworks (MOF) that breaks down carbon dioxide into harmless organic materials.
This has been a holy grail for scientists for years. Previously, there’s been some success using high-energy ultraviolet light. But UV rays make up only four per cent of the light Earth receives from the sun.
The challenge, according to a statement from UCF, has been finding a way for visible light to trigger the chemical transformation using affordable materials.
The visible range – the violet to red wavelengths – makes up the majority of the sun’s rays, but there are few materials that pick up these light colours to create the chemical reaction that transforms CO2 into fuel.
So far only rare and expensive materials such as platinum, rhenium and iridium were found to be capable of harvesting visible light, and the process was too costly to make it viable outside the laboratory.
Uribe-Romo appears to have cracked the code that opens the way to cleaning the air and producing solar fuel on an industrial-scale.
“This work is a breakthrough,’’ said Uribe Romo, in a video released on YouTube.
“Tailoring materials that will absorb a specific colour 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.’’
The findings of his research are published in the Journal of Materials Chemistry A.
According to the CFU statement, the chemists used titanium, a common nontoxic metal, and added organic molecules that act as light-harvesting antennae to see if that configuration would work.
The light harvesting antenna molecules – called N-alkyl-2-aminoterephthalates – were designed to absorb specific colours of light when incorporated in the metal-organic framework.
In this case Uribe-Romo synchronized his experiment for the colour blue, by assembling a blue LED photoreactor, “a glowing blue cylinder that looks like a tanning bed”.
Measured amounts of carbon dioxide were slowly fed into the photoreactor to see if the reaction would occur. It did.
“The goal is to continue to fine-tune the approach so we can create greater amounts of reduced carbon so it is more efficient,’’ Uribe-Romo said.
His next step is seeing if the other wavelengths of visible light will trigger the reaction with adjustments to the synthetic material. If it works, the process takes another big step toward reducing greenhouse gases.
“The idea would be to set up stations that capture large amounts of CO2, like next to a power plant,” said Uribe-Romo. “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.’’
Eventually, he suggests, homeowners could install rooftop shingles – instead of solar panel – that would photosynthesise clean air for the neighbourhood, and clean energy to power their homes.