A breakthrough imaging technique developed by Cornell researchers shows promise in decontaminating water by yielding surprising and important information about catalyst particles that can't be obtained any other way.

The researchers have developed a method that can image nonfluorescent catalytic reactions — reactions that don't emit light — on nanoscale particles. An existing method can image reactions that produce light, but that applies only to a small fraction of reactions, making the new technique potentially significant in fields ranging from materials engineering to nanotechnology and energy sciences.

Xianwen Mao, left, and Peng Chen, the Peter J.W. Debye Professor of Chemistry, are pictured in the microscope room in Olin Research Laboratory.

The researchers then demonstrated the technique in observing photoelectro-catalysis — chemical reactions involving interactions with light — a key process in environmental remediation.

Catalytic reactions occur when a catalyst, such as a solid particle, accelerates a molecular change. Imaging these reactions at the nanoscale as they happen, which the new technique allows scientists to do, can help researchers learn the optimal size and shape for the most effective catalyst particles.

In the paper, the researchers applied the new technique to image the oxidation of hydroquinone, a micropollutant found in water, on bismuth vanadate catalyst particles, and discovered previously unknown behaviors of catalysts that helped render hydroquinone non-toxic.

Previously, the research group pioneered the application of single-molecule fluorescence imaging, a noninvasive, relatively inexpensive and easily implemented method that allows researchers to observe chemical reactions in real time. Because the method was limited to fluorescent reactions, however, the team worked for years to seek a more widely applicable method.

The technique they discovered relies on competition between fluorescent and nonfluorescent reactions. The competition suppresses the fluorescent reaction, allowing it to be measured and mapped, which in turn provides information about the nonfluorescent reaction.

The researchers named their method COMPetition Enabled Imaging Technique with Super-Resolution, or COMPEITS.

This highly generalizable technique can be broadly applied to image various classes of nonfluorescent systems, such as unlabeled proteins, neurotransmitters and chemical warfare agents, according to the researchers. Therefore, they expect COMPEITS to be a breakthrough technology with profound impacts on many fields, including energy science, cell biology, neuroscience, and nanotechnology.

For more information, contact Gillian Smith at This email address is being protected from spambots. You need JavaScript enabled to view it..


Photonics & Imaging Technology Magazine

This article first appeared in the September, 2019 issue of Photonics & Imaging Technology Magazine.

Read more articles from this issue here.

Read more articles from the archives here.