big win

Rice University team breaks records with new sunlight-to-hydrogen device

Rice University engineers have created a device that absorbs light, converts it into electricity, and then uses the electricity to split water molecules and generate hydrogen. Photo courtesy Gustavo Raskoksy/Rice University

A team of Rice University engineers have developed a scalable photoelectrochemical cell that converts sunlight into clean hydrogen at a record-setting pace.

The lab led by Aditya Mohite, an associate professor at Rice, published the findings in a study in Nature Communications late last month, in collaboration with the National Renewable Energy Laboratory, which is backed by the Department of Energy. In it, the team details how they created a device that absorbs light, converts it into electricity, and then uses the electricity to split water molecules and generate hydrogen.

Austin Fehr, a chemical and biomolecular engineering doctoral student at Rice and one of the study’s lead authors, says in a statement that the device "could open up the hydrogen economy and change the way humans make things from fossil fuel to solar fuel."

The device has a high solar-to-hydrogen conversion efficiency rate of 20.8 percent, which has yet to be reached with this type of technology, according to a release from Rice. In addition to its speed, this device is groundbreaking because it uses low-cost metal-halide perovskite semiconductors to power the reaction.

A photoreactor developed by Rice University’s Mohite research group and collaborators achieved a 20.8 percent solar-to-hydrogen conversion efficiency. Photo courtesy Gustavo Raskoksy/Rice University

“Using sunlight as an energy source to manufacture chemicals is one of the largest hurdles to a clean energy economy,” Fehr says in the statement. “Our goal is to build economically feasible platforms that can generate solar-derived fuels. Here, we designed a system that absorbs light and completes electrochemical water-splitting chemistry on its surface.”

To create the device the Mohite lab turned their existing solar cell into a reactor to split water into oxygen and hydrogen. However they continued running into issues with the semiconductors being "extremely unstable in water," according to Rice.

After two years of trials and errors, the team uncovered that by adding two layers of barriers to the semiconductors they were able to reach these record-breaking efficiency rates.

The team has also shown uses for their double barrier design with different semiconductors and for different reactions.

“We hope that such systems will serve as a platform for driving a wide range of electrons to fuel-forming reactions using abundant feedstocks with only sunlight as the energy input,” Mohite says in the statement.

The device joins another game-changing product shared in a Rice research study in recent weeks. Last month, a Rice University lab led by Haotian Wang, the William Marsh Rice Trustee Chair and an associate professor at Rice, shared their findings on how their simple plug-and-play device removes carbon dioxide from air capture to induce a water-and-oxygen-based electrochemical reaction.

Rice also recently opened registration for its 20th anniversary of Energy Tech Venture Day. Click here to register for the event on Sept. 21.

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A View From HETI

Hobby Airport's new solar canopy is operating at 100% capacity. Photo courtesy Houston Airports.

Houston's William P. Hobby Airport is generating its own clean energy.

Houston Aiports announced that Hobby's red garage is now home to a "solar canopy" that is producing energy at 100 percent capacity to power daily operations. The photovoltaic (PV) solar system generated more than 1.1 gigawatt-hours of electricity in testing, and is expected to produce up to 1 megawatt-hour now that it's operating at full power.

“This project is proof that sustainability can be practical, visible and directly tied to the passenger experience,” Jim Szczesniak, director of aviation for Houston Airports, said in a news release. “Passengers now park under a structure that shields their cars from the Texas sun while generating clean energy that keeps airport operations running efficiently, lowering overall peak demand electrical costs during the day and our carbon footprint. It’s a win for travelers, the city and the planet.”

The project was completed by Texas A&M Engineering Experiment Station (TEES) and CenterPoint Energy. It's part of Houston Airport's efforts to reduce carbon emissions by 40 percent over its 2019 baseline.

In a separate announcement, the airport system also shared that it recently reached Level 3 in the Airports Council International (ACI) Airport Carbon Accreditation program after reducing emissions by 19 percent in three years. This includes reductions at George Bush Intercontinental Airport (IAH), Hobby and Ellington Airport/Houston Spaceport.

The reductions have come from initiatives such as adding electric vehicles to airport fleets, upgrading airfield lighting with LED bulbs, adding smarter power systems to terminals, and improving IAH's central utility plant with more efficient equipment. Additionally, the expansion to Hobby's West Concourse and renovations at IAH Terminal B incorporate cleaner equipment and technology.

According to Houston Airports, from 2019 to 2023:

  • IAH reduced emissions by 17 percent
  • Hobby reduced emissions by 32 percent
  • Ellington Airport reduced emissions by 4 percent

"I see firsthand how vital it is to link infrastructure with sustainability,” Houston City Council Member Twila Carter, chair of the council’s Resilience Committee, said in the release. “Reducing carbon emissions at our airports isn’t just about cleaner travel — it’s about smarter planning, safer communities and building a Houston that can thrive for generations to come.”

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