Researchers at the National University of Singapore really did have a lightbulb moment when a power trip in their laboratory changed the results of an experiment into water electrolysis.
The electrical shutdown in 2019 accidentally turned off all the lights in the lab and allowed them to observe something that had not previously been witnessed. They found that light can trigger a new mechanism in a nickel based catalytic material used extensively in water electrolysis.
This has led to a serendipitous scientific discovery that could revolutionise the way water is broken down to release hydrogen gas - crucial to many industrial processes.
“This drop in performance, nobody has ever noticed it before, because no one has ever done the experiment in the dark.”
“We discovered that the redox centre for electro-catalytic reaction is switched between metal and oxygen, triggered by light,” said associate professor Xue Jun Min, who led the project along with Dr Wang Xiaopeng and Dr Vincent Lee Wee Siang. “This largely improves the water electrolysis efficiency.”
The researchers, from the department of materials science & engineering at the NUS College of Design & Engineering (CDE), say the result is a more energy-efficient method of obtaining hydrogen. The new finding can potentially open up new and more effective methods of producing the gas, putting this environmentally friendly source of fuel within reach of more industries and people.
Had the experiment gone according to plan, Professor Xue and his team may not have come across their groundbreaking discovery. Back then, the ceiling lights in the research lab were usually turned on 24 hours a day.
Returning the day after that exceptional night when the lights went off, the researchers found that the performance of the nickel oxyhydroxide based material in the water electrolysis experiment had fallen drastically.
“This drop in performance, nobody has ever noticed it before, because no one has ever done the experiment in the dark,” said Professor Xue. “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, while the nickel-based material is very commonly used. In order to establish that they were on the verge of discovering something groundbreaking, Xue and his team repeated the experiment numerous times.
They dug deeper into the mechanics behind such a phenomenon and even repeated the experiment outside of Singapore to ensure that their findings were consistent. Three years on the team were finally able to share their findings publicly in a paper.
Building on the findings, the researchers are now working on designing a new way to improve industrial processes to generate hydrogen. Xue is considering making the water-containing cells 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,” he said. “More hydrogen can be produced in a shorter amount of time, with less energy consumed.”
Hydrogen gas is used in many industries. Food companies use it to turn unsaturated oils and fats into saturated ones, which gives 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 sulphur content from oil.
Moreover, hydrogen can potentially be used as a sustainable fuel - hydrogen produces no emissions as it burns upon reacting with oxygen, and no ignition is needed. It is also easier to store, making it more reliable than solar-powered batteries.
Professor Xue is glad that the findings from his team of researchers could contribute to scientific discovery. He thinks that the way to develop science is not to keep finding new ways to do what has already been done, but to constantly push the boundaries.
“It’s only through accumulation of new knowledge that we can improve society progressively,” he said.
The discovery of Professor Xue and his team is detailed in a research paper published in Nature journal. The breakthrough was achieved in collaboration with Dr Xi Shibo from the Institute of Sustainability for Chemicals, Energy & Environment; Dr Yu Zhigen from the Institute of High Performance Computing; and Dr Wang Hao, also from NUS CDE.