Rice University engineers develop hydrogen from sunlight

Rice University engineers can turn sunlight into hydrogen with record-breaking efficiency thanks to a device that combines next-generation halide perovskite semiconductors with electrocatalysts in a single, durable, cost-effective and scalable device.

The new technology is a significant step forward for clean energy and could serve as a platform for a wide range of chemical reactions that use solar-harvested electricity to convert feedstocks into fuels.

The lab of chemical and biomolecular engineer Aditya Mohite built the integrated photoreactor using an anticorrosion barrier that insulates the semiconductor from water without impeding the transfer of electrons. According to a study published in Nature Communications, the device achieved a 20.8% solar-to-hydrogen conversion efficiency.

The device is known as a photoelectrochemical cell because the absorption of light, its conversion into electricity and the use of the electricity to power a chemical reaction all occur in the same device. Until now, using photoelectrochemical technology to produce green hydrogen was hampered by low efficiencies and the high cost of semiconductors.

The Mohite lab and its collaborators created the device by turning their highly-competitive solar cell into a reactor that could use harvested energy to split water into oxygen and hydrogen. The challenge they had to overcome was that halide perovskites are extremely unstable in water and coatings used to insulate the semiconductors ended up either disrupting their function or damaging them.

After lengthy trials failed to yield the desired result, the researchers finally came across a winning solution.

The researchers showed their barrier design worked for different reactions and with different semiconductors, making it applicable across many systems.

Rice graduate students Ayush Agrawal and Faiz Mandani are lead authors on the study alongside Fehr. The work was also authored in part by the National Renewable Energy Laboratory, which is operated by Alliance for Sustainable Energy LLC for the Department of Energy.

Mohite is an associate professor of chemical and biomolecular engineering and the faculty director of the Rice Engineering Initiative for Energy Transition and Sustainability, or REINVENTS. Wong is the Tina and Sunit Patel Professor in Molecular Nanotechnology, chair and professor of chemical and biomolecular engineering, and a professor of chemistry, materials science and nanotechnology, as well as civil and environmental engineering.

The research was supported by the Department of Energy, SARIN Energy Inc. and Rice’s Shared Equipment Authority.