As the world moves to decarbonize transportation, hydrogen has emerged as a key contender, especially for applications where batteries fall short.
While electric motors work well for passenger cars, their energy density and recharge limitations make them impractical for heavy-duty vehicles, long-haul trucks, ships, and aircraft.
“Passenger cars can have a battery, but heavy trucks, ships or aircraft cannot use a battery to store the energy,” said Jianwu Sun, associate professor at Linköping University (LiU), Sweden. “For these means of transport, we need to find clean and renewable energy sources, and hydrogen is a good candidate.”
Sun and his team are developing materials that can produce hydrogen from water using sunlight alone. This form of “green” hydrogen could power transport sectors without viable battery-based systems.
Three-layer system shows dramatic performance jump
The LiU team’s latest study introduces a new material that drastically improves solar hydrogen output. The researchers built a layered structure combining cubic silicon carbide (3C-SiC), cobalt oxide (Co₃O₄), and a catalyst layer of nickel hydroxide (Ni(OH)₂).
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Sun said the goal was to analyze how each layer contributes. “It’s a very complicated structure, so our focus in this study has been to understand the function of each layer and how it helps improve the properties of the material.”
When exposed to sunlight, the material generates electrical charges that split water into hydrogen and oxygen. A major hurdle in such systems is charge recombination, where positive and negative charges cancel out before triggering the reaction.
Close-up of the three-layer solar material developed for hydrogen fuel production, with a water droplet highlighting its reactive surface. Credit – Linköping University/Olov Planthaber
By integrating the three layers, the material achieves better charge separation. The team reports an eightfold improvement in performance compared to using 3C-SiC alone.
Pushing toward truly green hydrogen
Currently, nearly all hydrogen in the market is “gray” hydrogen, made using fossil fuels. One metric ton of gray hydrogen can emit up to 10 tons of CO₂. This process undermines its role as a clean fuel.
“Green” hydrogen, by contrast, uses renewable electricity for water splitting. Yet even this method often depends on energy sources beyond direct sunlight. Sun and his team aim to cut that reliance.
Their vision is to use only solar energy to power the reaction. This approach would lower costs and eliminate carbon emissions from the process.
The 10% efficiency target still ahead
While promising, the technology is not yet commercially ready. Most current materials for solar water splitting operate at just 1–3% efficiency.
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For “green” hydrogen to scale, materials must hit at least 10% efficiency. Sun believes this is achievable. “It may take around five to 10 years for the research team to develop materials that reach the coveted 10% limit.”
Reaching that benchmark would mark a turning point for the hydrogen economy. It would enable low-cost, carbon-free hydrogen at a scale large enough to support industrial use and transportation. If successful, the layered material developed by Sun’s team could become a cornerstone of clean fuel infrastructure for decades ahead.
Aamir Khollam Aamir is a seasoned tech journalist with experience at Exhibit Magazine, Republic World, and PR Newswire. With a deep love for all things tech and science, he has spent years decoding the latest innovations and exploring how they shape industries, lifestyles, and the future of humanity.
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