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

The project would nearly eliminate the emissions associated with power and steam generation at the Dow plant in Seadrift, Texas. Getty Images

Dow, a major producer of chemicals and plastics, wants to use next-generation nuclear reactors for clean power and steam at a Texas manufacturing complex instead of natural gas.

Dow's subsidiary, Long Mott Energy, applied Monday to the U.S. Nuclear Regulatory Commission for a construction permit. It said the project with X-energy, an advanced nuclear reactor and fuel company, would nearly eliminate the emissions associated with power and steam generation at its plant in Seadrift, Texas, avoiding roughly 500,000 metric tons of planet-warming greenhouse gas emissions annually.

If built and operated as planned, it would be the first U.S. commercial advanced nuclear power plant for an industrial site, according to the NRC.

For many, nuclear power is emerging as an answer to meet a soaring demand for electricity nationwide, driven by the expansion of data centers and artificial intelligence, manufacturing and electrification, and to stave off the worst effects of a warming planet. However, there are safety and security concerns, the Union of Concerned Scientists cautions. The question of how to store hazardous nuclear waste in the U.S. is unresolved, too.

Dow wants four of X-energy's advanced small modular reactors, the Xe-100. Combined, those could supply up to 320 megawatts of electricity or 800 megawatts of thermal power. X-energy CEO J. Clay Sell said the project would demonstrate how new nuclear technology can meet the massive growth in electricity demand.

The Seadrift manufacturing complex, at about 4,700 acres, has eight production plants owned by Dow and one owned by Braskem. There, Dow makes plastics for a variety of uses including food and beverage packaging and wire and cable insulation, as well as glycols for antifreeze, polyester fabrics and bottles, and oxide derivatives for health and beauty products.

Edward Stones, the business vice president of energy and climate at Dow, said submitting the permit application is an important next step in expanding access to safe, clean, reliable, cost-competitive nuclear energy in the United States. The project is supported by the Department of Energy’s Advanced Reactor Demonstration Program.

The NRC expects the review to take three years or less. If a permit is issued, construction could begin at the end of this decade, so the reactors would be ready early in the 2030s, as the natural gas-fired equipment is retired.

A total of four applicants have asked the NRC for construction permits for advanced nuclear reactors. The NRC issued a permit to Abilene Christian University for a research reactor and to Kairos Power for one reactor and two reactor test versions of that company's design. It's reviewing an application by Bill Gates and his energy company, TerraPower, to build an advanced reactor in Wyoming.

X-energy is also collaborating with Amazon to bring more than 5 gigawatts of new nuclear power projects online across the United States by 2039, beginning in Washington state. Amazon and other tech giants have committed to using renewable energy to meet the surging demand from data centers and artificial intelligence and address climate change.

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