Hydrogen peroxide is a chemical best known as a disinfectant, but it has far more powerful uses. Packed with chemical energy, it is strong enough to fuel rockets.
On Earth, it also shows promise as a clean energy source for fuel cells and other green technologies.
When hydrogen peroxide releases its stored energy, it breaks down into nothing more than water, making it an attractive option for sustainable energy.
Now, researchers at King Abdullah University of Science and Technology (KAUST), working with colleagues in China and the United States, have developed a material that sets a new standard for producing hydrogen peroxide with sunlight.
Their breakthrough catalyst, described in the Journal of the American Chemical Society, is far more efficient than any previously reported system.
Currently, most hydrogen peroxide is made at an industrial scale using processes that rely on toxic organic solvents, which harm the environment. Scientists have long sought cleaner methods, and one of the most promising is photocatalysis—using sunlight and a catalyst to drive the production of hydrogen peroxide directly from water and oxygen in the air.
Here’s how it works: when a semiconductor photocatalyst is exposed to sunlight, it absorbs energy from photons and generates pairs of charge carriers, known as electrons and holes.
The electrons then participate in chemical reactions at the catalyst’s surface, ideally converting oxygen molecules into hydrogen peroxide. But the process is tricky.
Oxygen can follow several reaction pathways, and not all of them are useful. The desired route, which produces hydrogen peroxide, involves two electrons. Unfortunately, oxygen more often follows a four-electron pathway that produces only water or a one-electron route that leads to unstable byproducts.
To solve this challenge, the KAUST team focused on controlling the catalyst at the atomic level. They began with tungsten trioxide (WO₃), a well-known photocatalyst, and then carefully added isolated copper atoms to its surface.
These copper atoms serve as active sites that capture oxygen molecules and guide them toward the two-electron pathway needed for hydrogen peroxide production.
“Compared to earlier catalysts, our material has well-defined single-atom sites where the electronic states driving the reaction can be fine-tuned,” explained researcher Chengyang Feng. “By adjusting the interaction between the copper sites and the tungsten support, we were able to achieve record performance.”
The results were striking. Under visible light, the new catalyst produced 102 micromoles of hydrogen peroxide per hour—17.3 times more than tungsten trioxide alone and significantly higher than any previously reported photocatalyst.
The researchers now plan to test the system under real-world conditions, scale it up, and study its stability over long periods.
They also hope to explore ways to integrate it into practical devices. If successful, this innovation could help pave the way for greener chemical processes and sustainable energy systems powered by something as simple as sunlight, oxygen, and water.
