Scientists at the University of California, Santa Cruz, say the solar-microbial device can also improve the efficiency of waste water treatment.
Writing in the American Chemical Society journal ACS Nano, the researchers report their hybrid device combines a microbial fuel cell and a type of solar cell called a photoelectrochemical cell.
In the microbial component, bacteria degrade organic matter in the wastewater, generating electricity which is delivered to the solar component to aid in electrolysis, the splitting of water into hydrogen and oxygen.
Such biological and solar devices can each produce hydrogen on their own but require an external voltage to do so, the researchers said; in contrast, the new hybrid device is self-driven and self-sustained, because the combined energy from the organic matter harvested by the microbial fuel cell and the sunlight captured by the photochemical cell is sufficient to drive the electrolysis of water.
"The only [required] energy sources are wastewater and sunlight," UC Santa Cruz chemistry professor Yat LI said.
"The successful demonstration of such a self-biased, sustainable microbial device for hydrogen generation could provide a new solution that can simultaneously address the need for waste water treatment and the increasing demand for clean energy."