Artificial Photosynthesis Device Becomes More Efficient With Each Use

Technologies that turn light and water into carbon-free hydrogen fuel could have unlimited potential, but they have not been developed properly yet. Now, scientists at the University of Michigan, with the help of the Lawrence Livermore National Laboratory, have engineered a water-splitting device made with cheap and abundant materials that become more efficient with each use.

“We discovered an unusual property in the material that enables it to become more efficient and stable,” said Francesca Toma, a staff scientist in the Chemical Sciences Division of the Lawrence Berkeley National Laboratory and senior author of the new paper. 

“Our discovery is a real game-changer. I’ve never seen such stability.”

The novel device was invented by Zetian Mi, University of Michigan professor of electrical and computer engineering. The device is practically made of an inexpensive semiconductor that is widely used in everyday electronics and has been found to double the efficiency and stability of previous similar technologies.

“The unique platform we have developed over the past decade is not only suited for solar hydrogen production, but has been used very effectively for converting carbon dioxide to clean chemicals and fuels, such as methane, methanol, formic acid, and syngas,” Mi said. “What strikes me most, however, is their stability in numerous studies performed by us and our collaborators.”

In most cases, the efficiency of an artificial photosynthesis device falls significantly after just a few hours of use but this new material began producing more free electrons and also got better at recruiting them to split water with each use.

“In other words, instead of getting worse, the material got better,” the lead author of the study Guosong Zeng, a postdoctoral scholar in Berkeley Lab’s Chemical Sciences Division, said. After further study that included computer simulations, the team concluded that this increase in efficiency could be attributed to the gallium nitride in the device.

The researchers now hope to use these new findings to design and build more efficient artificial photosynthesis devices at a lower cost. The study is published in the journal Nature Materials.