ANN ARBOR—An exotic interaction between light and metal can be harnessed to make chemical reactions more sustainable, but the physics behind it has been widely debated in the field.
Now, a study from the University of Michigan has shown how a light-harvesting metal transfers energy to a catalytic metal, opening the way for better catalyst designs.
Catalysts are mediators of chemical reactions: they can make reactions happen at lower temperatures, reducing the energy needed, and they can also give an edge to a desired reaction pathway, producing more of the target chemical and less waste.
A new kind of catalyst can be made from so-called plasmonic metals that are good at capturing the light, but they aren’t terrific at guiding reactions. To improve their effectiveness, researchers have been peppering them with materials that are better catalysts, improving reactions related to fuel production and common household products like toothpaste, for example.
“The difficulty with earlier experiments was that there were many different exposed surfaces, so it gets very difficult to interpret your results because of the complexity of the nanoparticles,” said Umar Aslam, U-M doctoral student in chemical engineering,
Now, Aslam and his colleagues in the research group of Suljo Linic, a professor of chemical engineering and a pioneer in plasmonic catalysis, have shown how the energy moves. Rather than energetic electrons hopping from the light-capturer to the catalyst, the plasmonic metal is acting more like a radio antenna, with the catalyst as the receiver, Aslam said.
Their experiment, published in the journal Nature Nanotechnology, was the first to convincingly show that this mechanism is at work.
“We described how plasmonic…