A serendipitous scientific discovery by researchers at the National University of Singapore could potentially revolutionize the way water is broken down to release hydrogen gas.

The team found that light can trigger a new mechanism in a catalytic material used extensively in water electrolysis, where water is broken down into hydrogen and oxygen. The result is a more energy-efficient method of obtaining hydrogen.

The team detailed their discovery in a research paper published in the scientific journal Nature.

The team, led by Associate Professor Xue Jun Min, Dr Wang Xiaopeng and Dr Vincent Lee Wee Siang from the Department of Materials Science and Engineering under the NUS College of Design and Engineering (NUS CDE), found that light can trigger a new mechanism in a catalytic material used extensively in water electrolysis.

This breakthrough was achieved in collaboration with Dr Xi Shibo from the Institute of Sustainability for Chemicals, Energy and Environment under the Agency for Science, Technology and Research (A*STAR); Dr Yu Zhigen from the Institute of High Performance Computing under A*STAR; and Dr Wang Hao from the Department of Mechanical Engineering under the NUS CDE.Assoc Prof Xue said, “We discovered that the redox center for electro-catalytic reaction is switched between metal and oxygen, triggered by light. This largely improves the water electrolysis efficiency.”

The groundbreaking discovery made by Assoc Prof Xue Jun Min (center) and his team could improve affordability of hydrogen as source of clean energy. Image Credit: National University of Singapore. Click here for the largest image and more images.

The new finding can potentially open up new and more effective industrial methods of producing hydrogen and putting this environmentally friendly source of fuel within the reach of more people and industries.

The accidental breakthrough

Under normal circumstances, Assoc Prof Xue and his team may not have been able to come across such a groundbreaking discovery. But an accidental power off tripping of the ceiling lights in his laboratory almost three years ago allowed them to observe something that the global scientific community has not yet managed to do.

Back then, the ceiling lights in Assoc Prof Xue’s research lab were usually turned on all 24 hours a day. One night in 2019, the lights went off due to a power off trip. When the researchers returned the next day, they found that the performance of a nickel oxyhydroxide-based material in the water electrolysis experiment, which had continued in the dark, had fallen drastically.

Assoc Prof Xue noted, “This drop in performance, nobody has ever noticed it before, because no one has ever done the experiment in the dark. Also, the literature says that such a material shouldn’t be sensitive to light; light should not have any effect on its properties.”

The electro-catalytic mechanism in water electrolysis is a very well researched topic, and the nickel-based material is a very common catalytic material. Hence, in order to establish that they were on the verge of discovering something groundbreaking, Assoc Prof Xue and his team embarked on numerous repeated experiments. They dug deeper into the mechanics behind such a phenomenon. They even repeated the experiment outside of Singapore to ensure that their findings were consistent.

Now three years into the research Assoc Prof Xue and his team were finally able to share their findings publicly in a paper.

Next steps

With their findings, the team is now working on designing a new way to improve industrial processes to generate hydrogen. Assoc Prof Xue is suggesting making the cells containing water to be transparent, so as to introduce light into the water splitting process.

“This should require less energy in the electrolysis process, and it should be much easier using natural light. More hydrogen can be produced in a shorter amount of time, with less energy consumed,” said Assoc Prof Xue.

Food companies use hydrogen gas to turn unsaturated oils and fats into saturated ones, which give us margarine and butter. Hydrogen is also used to weld metals together, as it can generate a high temperature of 4,000° C. The petroleum industry uses the gas to remove the sulfur content from oil.

Hydrogen can potentially be used as a fuel. Long-touted as a sustainable fuel, hydrogen fuel produces no emissions as it burns upon reacting with oxygen – no ignition is needed, making it a cleaner and greener fuel source. Once the storage issues are worked out hydrogen could be more reliable than solar-powered batteries.


Considering incoming light as an accelerant to a catalyst sounds like a fake. But three years of testing and experimentation seems justified and was duly undertaken.

Congratulations are in order. The team showed great situational awareness from the power outage by not just blowing off the anomaly of the running test and chasing the facts to the optimum conclusion.


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