From Ohio State University
: Chemistry finding could make solar energy more efficient
by Laura Arenschield/ Jan 20, 2020
Researchers have found a way to harness the entire spectrum of sunlight
Scientists for the first time have developed a single molecule that can absorb sunlight efficiently and also act as a catalyst to transform solar energy into hydrogen, a clean alternative to fuel for things like gas-powered vehicles.
This new molecule collects energy from the entire visible spectrum, and can harness more than 50% more solar energy than current solar cells can. The finding could help humans transition away from fossil fuels and toward energy sources that do not contribute to climate change.
The researchers outlined their findings in a study published today in Nature Chemistry. The research team was led by Claudia Turro, a chemistry professor and director of The Ohio State University Center for Chemical and Biophysical Dynamics.
The few attempts that relied on a single-molecule catalyst were also inefficient, Turro said, in part because they did not collect energy from the full visible spectrum of sunlight, and in part because the catalysts themselves degraded quickly.
Turro’s research team figured out how to make a catalyst out of just one molecule — a form of the element rhodium — which means less energy is lost, she said. And they figured out how to collect energy from infrared to ultraviolent — the entire visible spectrum. The system this research team designed is nearly 25 times more efficient with low-energy near-infrared light than previous single-molecule systems operative with ultraviolet photons, according to the study.
In the study, the researchers used LEDs to shine light onto acid solutions containing the active molecule. When they did, they found that hydrogen was produced.
“I think the reason it works is because the molecule is difficult to oxidize,” she said. “And we have to have renewable energy. Just imagine if we could use sunlight for our energy instead of coal or gas or oil, what we could do to address climate change.”
Before the research team’s finding can be put into real-world applications, Turro said, there is still much work to be done. Rhodium is a rare metal and producing catalysts from rhodium is expensive. The team is working on improving this molecule to produce hydrogen over a longer period of time and is working on building the catalyst out of less expensive materials.
This work was supported by the U.S. Department of Energy's Office of Science.