A study of aluminum nanoparticles by Rice University’s Laboratory for Nanophotonics found that octopods (left), sharp-pointed angled six-sided particles, are five times larger than nanocubes (center) and 10 times larger than 14-sided nanocrystals. Credit: Image courtesy of Lin Yuan / Rice University
Study: Suggested suggestions on aluminum ‘octopods’ increase the catalytic reaction.
Dots are important when constructing nanoparticles that carry out important chemical reactions using the power of light.
Researchers at Rice University’s Nanophotonics (LANP) laboratory have long known how the shape of a nanoparticle interacts with light, and their recent study shows how shape affects the microscopic effect of using light to produce important chemical reactions. doing.
In the comparative study, Linpu graduates Lin Yuan and Minhan Lu Lou and their colleagues studied aluminum nanoparticles with similar optical properties but different shapes. The most rounded had 14 sides and 24 bluetooth points. The other was solid-shaped, with six sides and eight 90-degree angles. The third, which the team called the “top cotopod,” also had six sides, but each of its eight corners ended in a point tip.
Research by Minhan L (left) and Lin Yuan, graduates of Rice University’s Laboratory for Nanophotonics, found that the shape of a nanocatalyst affects its ability to photocatalyze important chemical reactions. Credit: Photo by Jeff Fitlow / Rice
All three species have the ability to capture light from light and periodically release it in the form of super-energetic hot electrons that can accelerate catalytic reactions. Yuan, a chemist in the research group of Lanpi director Naomi Halas, conducted experiments to see how well each particle of photocatalysts did for the hydrogen dissociation reaction. Tests showed that octopods had a 10 times higher reaction rate than 14-sided nanocrystals and five times higher than nanocubes. Octopods also had less obvious activation energy, about 45% less than nanocubes and 49% less than nanocrystals.
Naomi Halas of Rice University is an engineer, chemist, and pioneer in the field of light-activated nanomaterials. Credit: Jeff Fitlow / Rice University
Yuan, co-lead author of the study, published in the Journal of the American Chemical Society, said the experiments showed that sharp angles increased efficiency. ACS Nano. “For octopods, the angle of inclination is 60 degrees, compared to 90 degrees for cubes and more rounded points on nanocrystals. Hence the smaller the angle, the greater the efficiency of the reaction. But how small the angle can be is limited by chemical synthesis. These are single crystals that prefer certain structures. You can’t create infinite more intensity. “
LANN, P.P. The physicist and study co-lead author of Nordlander’s research group examines the results of catalytic experiments by developing a theoretical model of the hot electron transfer process between light-activated aluminum nanoparticles and hydrogen atoms.
“We input light and micro-wavelengths,” Lou said. “Using these two aspects, we can predict which shape will produce the best catalyst.”
This work is part of an ongoing green chemistry effort by LANP to develop commercially viable light-activated nanocatalysts that can insert energy into chemical reactions with surgical precision. LNP has previously been shown to be a catalyst for the production of ethylene and syngas, the breakdown of ammonia to produce hydrogen fuel, and the breaking down of “chemicals forever.
Rice’s Stanley C., director of the Rice Small-Curl Institute. “This study shows that the shape of the photocatalyst can be used by other design element engineers to create photocatalysts with higher reaction rates and lower activation barriers,” said Moore Professor Halas. And Professor of Chemistry, Biochemistry, Physics and Astronomy, and Materials Science and Nanoengineering.
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References: Lin Yuan, Minhan Lou, Benjamin D. Clark, Minghe l Lou, Linan Zoo, Shu Tian, Christian R. Jacobson, Peter Nordlander and Naomi J. Halas, 12 August Gust 2020, “Morphology-dependent reaction of a plasmonic photocatalyst”. ACS Nano.
DOI: 10.1021 / acsnano.0c05383
Nordlander Weiss is chair and professor of physics and astronomy, and professor of electrical and computer engineering, and materials science and nanoengineering.
Additional study co-authors include Benjamin Clark, Minge Lou, Linan Xu, Xu Tian, and Christian Jacobson, all rice. The research was supported by the Welch Foundation (C-1220, C-1222), the Air Force Office of Physical Research (FA 9550-15-1-0022), and the Defense Threat Reduction Agency (HDTRA 1-16-1-0042). And the Department of Defense National Defense Science & Engineering Graduate Fellowship Program.
