April 3, 2026 by Yale University
Collected at: https://phys.org/news/2026-04-real-nanoscale-reduction-oxidation-solar.html
Solar-power photocatalysis—turning sunlight into energy—holds promise for sustainable and cost-efficient energy and chemical production. Advancing the technology, though, has been hindered by a lack of understanding of exactly how the process works. To that end, a team of Yale researchers has developed a technique that allows them to observe the sunlight-to-fuel conversion in real time, right down to the nanoscale. Specifically, they can see how the light-driven catalyst splits water into hydrogen and oxygen, and how electrons and holes move through the material.
The study is published in the Proceedings of the National Academy of Sciences.
“We are excited because this method lets us see a photocatalyst ‘in action’ with an unusual combination of realism and resolution,” said Shu Hu, professor of chemical & environmental engineering, who led the study.
New insights into solar-fuel reactions
This study introduces a new way to watch photocatalysts work in real time and at extremely small scales of about 10 nanometers. This overcomes a key limitation in the field, and could help improve technologies that use sunlight to produce clean fuels and chemicals.
Also, the researchers noted, the work reveals the precise division between two chemical reactions—reduction and oxidation. This insight could pave the way for designing better solar-fuel materials.
How the nanotip measurement system works
They created a system that simultaneously makes amperometric and potentiometric measurements. Amperometric measurements account for the number of electrons that flow. Potentiometric measurements determine the voltage, or force that propels the electrons. To do so, they created a “nanotip,” a very fragile nanoscale quartz tip with a nanometer-sized platinum wire in the center.
One challenge of their work was bringing the nanotip into physical contact with the surface without damaging it and maintaining very precise positional control. Hu said a major surprise of their work was that they could measure the electrical current of not only the metallic surfaces, but also the voltage of the semiconductor materials while under light.
Publication details
Tianyu Bo et al, Probing charge-transfer processes in Pt/TiO2 photocatalysts by amperometric/potentiometric photo-SECM, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2527861123
Journal information: Proceedings of the National Academy of Sciences
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