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HMNTL professor works to make chemical reactions more efficient

10/15/2020 10:33:53 AM Lizzie Roehrs

HMNTL professor Brian Cunningham, along with his team of graduate students and postdocs, is working to use light to make industrial chemical reactions more energy efficient.

“Our idea is that by using light, rather than heat, industrial chemical reactions can be more energy-efficient,” says Cunningham, the Intel Alumni Endowed Chair in the department of electrical and computer engineering at UIUC. “The research is an effort to develop “green chemistry” for commercially viable light-activated nanocatalysts that can insert energy into chemical reactions with a high degree of wavelength precision.”

Many industrial processes use heat to catalyze chemical reactions. Cunningham’s team is instead using sources such as LEDs and lasers to fuel those processes. They capture light using an optical nanostructure surface called a photonic crystal, which couples energy into gold nanoparticles that sit on the photonic crystal. The gold is a good electrical conductor that is full of electrons. 

“The reactive electrons are called ‘hot’ electrons due to their excited energy state, although their temperature is not elevated,” says Cunningham. “We show that the production of hot electrons drives a specific chemical reaction that needs reactive electrons to proceed forward.”

Cunningham’s work not only means a more efficient approach to production, but also a more environmentally friendly one

The applications for this work include the production of ethylene, splitting of ammonia to produce hydrogen fuel, and breaking apart plastics for light-activated recycling.

“Prior work by other research groups had already shown that gold nanoparticles could be used in this way, but our work showed for the first time that large gains in overall energy conversion efficiency from the light source to the gold could be achieved through the use of a photonic crystal surface as the intermediary,” says Cunningham.

Cunningham’s group, in collaboration with Prof. Srikanth Singamaneni’s group at Washington University recently published a paper in ACS Photonics describing this new approach. The first author is Qinglan Huang, an ECE student who completed her PhD in May, 2019, and is currently a postdoc at Stanford University.