How can we address rising global energy demands in a manner that supports both environmental and industrial goals?
One new Concordia graduate says the answer lies in solar energy conversion – with a twist.
“We are using photosynthesis principles to capture solar energy in a new way, using chemistry,” explains Francisco Yarur Villanueva (MSc 20), who recently earned his master’s degree from the Department of Chemistry and Biochemistry in Concordia’s Faculty of Arts and Science.
Typically, solar energy for artificial photosynthesis is captured employing expensive metals, such as iridium and ruthenium.
Villanueva’s work, recently published in the American Chemical Society journal Applied Nano Materials, applies chemistry principles to mimic photosynthesis, a process adopted by plants to convert energy in the form of light into useful chemical energy. This produces high-value-added chemicals that can be used for various applications while tackling the important and timely topic of worldwide resource scarcity.
The work relied on working with zinc-based nanowires to capture solar energy. How small are nano-sized objects? Think of the width of a hair on a human head and picture something 80,000 times smaller.
Villanueva modified these very thin wires with carbon nanoparticles and was able to successfully use the energy from the sun to drive reactions. “These devices are tailored for the photodegradation of organic contaminants and the production of solar fuels where the electronics are well understood,” he says.
Carbon dots and coffee grounds
“Francisco has used a combination of special techniques to coat a conductive glass slide in zinc oxide – typically found in sunscreen and calamine lotion – and carbon dots – a material formed through the high temperature decomposition of organics, like coffee grounds and orange peels,” explains Majewski.
“This combination makes a coating that can absorb light and convert it to an electrical charge, similar to what happens in a conventional solar panel.”
Another plus? By storing solar energy in chemical bonds, the sometimes-intermittent nature of the sun is no longer a problem.
In addition to positive environmental considerations, Villanueva’s cost-effective methods could spell big net gains for industrial actors.
“This film approach means there’s no need for extra extraction or purification steps, unlike conventional precious-metal-containing methods,” he says. “We are just using elements that are already earth-abundant.”
He adds that industries that could benefit from this technology include agriculture and pharmaceuticals.
“There are clear benefits to those working in field production. For the pharmaceutical industry, this is of particular interest as it allows for a cheaper, easier way to create drugs.”
Standout work from a young lab
Part of what makes Villanueva’s research so impressive is that the Solar Energy Conversion Group lab was only established in 2018. This is its first major project to be completed.
“It makes me and my colleagues feel really proud as a Concordia research group, but it was even more rewarding taking into account that our lab is not even two years old,” Villanueva says.
A number of other stakeholders also played a role in the project’s achievement.
“This highlights a successful collaboration within our department and the Centre for NanoScience Research, between our group and the Advanced Materials Lab, who are world leaders in carbon dot research,” Majewski notes.
“The work also showcases the high calibre and global scale of the research being conducted at Concordia that is enabled by the university’s continued commitment to sustainability and tight-knit scientific community.”
A passion for energy and the environment
Rafik Naccache, assistant professor of chemistry and biochemistry, supervised Villanueva’s undergraduate honours project. He is not surprised his former student has continued to combine his love of science with a strong interest in sustainability.
“Francisco was always interested in working with nanomaterials but was also passionate about energy and the environment.”
As an undergraduate, Villanueva’s work with Naccache on detecting heavy metals in water earned him a top author spot in Environmental Science: Nano, a leading journal in the field of environmental research.
“Think about the amount of sunlight and energy that hits the earth every day,” says Naccache. “If we can harvest just some of this energy, we can make groundbreaking advancements.”
Villanueva plans to continue his work on more projects using inexpensive materials to absorb and store light.
“I am now using kesterite nanocrystals – a copper sulfide-based mineral – to absorb infrared light, using LEDs that simulate the light of the sun.”
As research in the field advances, Villanueva’s work may only be the beginning of a much bigger discussion about global energy conservation.
“I am very proud of this research, and I am confident the Solar Energy Conversion Group at Concordia will keep attracting interest in the years to come.”
Read the cited paper: “Carbon Dot-Sensitized Photoanodes for Visible Light-Driven Organic Transformations.”