Researchers at the University of Michigan and McGill University in Montreal have created a device that uses sunlight to efficiently split fresh or salt water into hydrogen that may be used in fuel cells. The new machine, which mimics the process of photosynthesis, is capable of producing hydrogen fuel at twice the efficiency of previous technologies.
Producing only water as an emission, hydrogen is the cleanest burning fuel. However, its production has historically not been environmentally friendly or energy efficient. This new device may change all that, paving the way to a cleaner energy future. “If we can directly store solar energy as a chemical fuel, like what nature does with photosynthesis, we could solve a fundamental challenge of renewable energy,” said lead researcher Zetian Mi.
Unlike solar panels, which can only store energy if they are attached to a battery, the artificial photosynthesis device uses splits water to store solar energy as hydrogen fuel. Despite this fundamental difference from solar panels, the device is made from the same materials, such as silicon and gallium nitride, which is also found in LEDs.
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Small towers of gallium nitride generate an electric field to turn photons into free charges, which divide water into its two component elements, oxygen and hydrogen. In contrast with previous solar splitters, which had only reached 1 percent efficiency, Mi’s team managed to achieve a 3 percent solar-to-hydrogen efficiency. “Although the 3 percent efficiency might seem low, when put in the context of the 40 years of research on this process, it’s actually a big breakthrough,” Mi said. “Natural photosynthesis, depending how you calculate it, has an efficiency of about 0.6 percent.” The device, further developed, may even be able to pull carbon dioxide from the atmosphere, potentially alleviating the impact of climate change.
Images via Faqrul A. Chowdhury/McGill University