When exposed to sunlight, star-shaped gold nanoparticles coated with a semiconductor allow efficient production of hydrogen from water. Image: Ashley Pennington/Rutgers University-New Brunswick.Star-shaped gold nanoparticles coated with a semiconductor can produce hydrogen from water over four times more efficiently than other methods. This finding could open the door to improved storage of solar energy and other advances that could boost renewable energy use and combat climate change, according to researchers at Rutgers University-New Brunswick.
"Instead of using ultraviolet light, which is the standard practice, we leveraged the energy of visible and infrared light to excite electrons in gold nanoparticles," said Laura Fabris, associate professor in the Department of Materials Science and Engineering, who led the work with Fuat Celik, assistant professor in the Department of Chemical and Biochemical Engineering. "Excited electrons in the metal can be transferred more efficiently into the semiconductor, which catalyzes the reaction."
The researchers, who report their findings in a paper in Chem, focused on photocatalysts, which harness sunlight to make faster or cheaper reactions. Titanium dioxide illuminated by ultraviolet (UV) light is often employed as such a catalyst, but using ultraviolet light is inefficient.
In the study, the Rutgers researchers tapped visible and infrared light, which gold nanoparticles can absorb more quickly, and then transferred some of the electrons generated as a result of this light absorption to nearby materials like titanium dioxide.
To do this, the engineers coated gold nanoparticles with titanium dioxide and exposed the material to UV, visible and infrared light, and studied how electrons jump from gold to the material. The researchers found that the electrons, which trigger reactions, produced hydrogen from water over four times more efficiently than had been achieved by previous efforts. Hydrogen can be used to store solar energy and then combusted for energy when the sun isn’t shining.
"Our outstanding results were ever so clear," Fabris said. "We were also able to use very low temperature synthesis to coat these gold particles with crystalline titanium. I think both from the materials perspective and the catalysis perspective, this work was very exciting all along. And we were extremely lucky that our doctoral students, Supriya Atta and Ashley Pennington, were also as excited about it as we were."
"This was our first foray," she added, "but once we understand the material and how it operates, we can design materials for applications in different fields, such as semiconductors, the solar or chemical industries, or converting carbon dioxide into something we can use. In the future, we could greatly broaden the ways we take advantage of sunlight."
This story is adapted from material from Rutgers University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.