New research from Rice and UH has helped boost the lifespan of CO2RR systems, a newer technology used for carbon capture. Photo via htxenergytransition.org

A team of researchers led by professors from two Houston universities has discovered new methods that help stabilize an emerging technique known as carbon dioxide reduction reaction, or CO2RR, that is used for carbon capture and utilization processes.

The team led by Rice University’s Haotian Wang, associate professor in chemical and biomolecular engineering, and Xiaonan Shan, associate professor of electrical and computer engineering at University of Houston, published its findings in a recent edition of the journal Nature Energy.

CO2RR is an emerging carbon capture and utilization technique where electricity and chemical catalysts are used to convert carbon dioxide gas into carbon-containing compounds like alcohols, ethylene, formic acids or carbon monoxide, according to a news release from Rice. The result can be used as fuels, chemicals or as starting materials to produce other compounds.

The technology is used in commercial membrane electrode assembly (MEA) electrolyzers to convert carbon dioxide into valuable compounds, but the technology isn’t perfected. A significant challenge in CO2RR technology has been the accumulation of bicarbonate salt crystals on the backside of the cathode gas diffusion electrode and within the gas flow channels. The salt precipitates block the flow of carbon dioxide gas through the cathode chamber, which reduce the performance and can cause a failure of the electrolyzers.

The goal in the study was to understand why and how bicarbonate salts form during this reaction. The Rice and UH teams worked together using operando Raman spectroscopy, which is a technique that allows researchers to study the structure of materials and any precipitates that adhere to them while the device is functioning.

“By utilizing operando Raman spectroscopy and optical microscopy, we successfully tracked the movement of bicarbonate-containing droplets and identified their migration pattern,” Shan said in the release. “This provided us the information to develop an effective strategy to manage these droplets without interrupting system stability.”

Next, the team worked to prevent the salt crystals from forming. First, they tested lowering the concentration of cations, like sodium or potassium, in the electrolyte to slow down the salt formation. This method proved to be effective.

They also coated the cathode with parylene, a synthetic polymer that repels water, like Teflon, which also notably improved the stability of the electrolyzer and prevented salt accumulation.

“Inspired by the waxy surface of the lotus leaf which causes water droplets to bead up and roll off, carrying off any dirt particles with it and leaving the leaf’s surface clean, we wondered if coating the gas flow channel with a nonstick substance will prevent salt-laden droplets from staying on the surface of the electrodes for too long and, therefore, reduce salt buildup.” Wang said in the release.

According to Wang, these relatively simple discoveries can extend the operational lifespan of CO2RR systems from a few hundred hours to over 1,000 hours.

The findings also have major implications for commercial applications, Shan added.

“This advancement paves the way for longer-lasting and more reliable (CO2RR) systems, making the technology more practical for large-scale chemical manufacturing,” Shan said in the release. “The improvements we developed are crucial for transitioning CO2 electrolysis from laboratory setups to commercial applications for producing sustainable fuels and chemicals.”

Rice professor and Solidec co-founder Haotian Wang's research enables CO2 to be converted into valuable chemicals and fuels. Photo courtesy Welch Foundation.

Houston clean energy pioneer earns prestigious Welch Foundation award

Awards Season

A Rice University professor has earned a prestigious award from the Houston-based Welch Foundation, which supports chemistry research.

The foundation gave its 2025 Norman Hackerman Award in Chemical Research to Haotian Wang for his “exceptionally creative” research involving carbon dioxide electrochemistry. His research enables CO2 to be converted into valuable chemicals and fuels.

The award included $100,000 and a bronze sculpture.

“Dr. Wang’s extensive body of work and rigorous pursuit of efficient electrochemical solutions to practical problems set him apart as a top innovator among early-career researchers,” Catherine Murphy, chairwoman of the foundation’s Scientific Advisory Board, said in a news release.

Wang is an associate professor in the Department of Chemical and Biomolecular Engineering at Rice. The department’s Wang Group develops nanomaterials and electrolyzers for energy and environmental uses, such as energy storage, chemical and fuel generation, green synthesis and water treatment.

Wang also is co-founder of Solidec, a Houston startup that aims to turn his innovations into low-carbon fuels, carbon-negative hydrogen and carbon-neutral peroxide. The startup extracts molecules from water and air, then transforms them into pure chemicals and fuels that are free of carbon emissions.

Solidec has been selected for Chevron Technology Ventures’ catalyst program, a Rice One Small Step grant, a U.S. Department of Energy grant, and the first cohort of the Activate Houston program.

“Dr. Wang’s use of electrochemistry to close the carbon cycle and develop renewable sources of industrial chemicals directly intersects with the Welch Foundation mission of advancing chemistry while improving life,” Fred Brazelton, chairman and director of the Welch Foundation, said in the release.

Ramamoorthy Ramesh, executive vice president for research at Rice University, added: “We are proud to (Dr. Wang) at Rice. He’s using chemical engineering to solve a big problem for humanity, everything that the Welch Foundation stands for.”

Last year, the Hackerman Award went to Baylor College of Medicine's Livia Schiavinato Eberlin, who's known for her groundbreaking work in the application of mass spectrometry technologies, which are changing how physicians treat cancer and analyze tissues. Read more here.

Led by Haotian Wang (left) and Feng-Yang Chen, the Rice University team published a study this month detailing how its reactor system sustainably converts waste into ammonia. Photo by Jeff Fitlow/Rice University

Houston lab develops reactor that sustainably turns waste into ammonia

seeing green

A team of Rice University engineers has developed a reactor design that can decarbonize ammonia production, produce clean water and potentially have applications in further research into other eco-friendly chemical processes.

Led by Rice associate professor Haotian Wang, the team published a study this month in the journal Nature Catalysis that details how the new reactor system sustainably and efficiently converts nitrates (common pollutants found in industrial wastewater and agricultural runoff) into ammonia, according to the university. The research was supported by Rice and the National Science Foundation.

“Our findings suggest a new, greener method of addressing both water pollution and ammonia production, which could influence how industries and communities handle these challenges,” Wang says in a statement. “If we want to decarbonize the grid and reach net-zero goals by 2050, there is an urgent need to develop alternative ways to produce ammonia sustainably.”

Other methods of creating ammonia include the Haber-Bosh process and electrochemical synthesis. The Haber-Bosh process requires large-scale centralized infrastructure and high temperature and pressure conditions. Meanwhile, electrochemical synthesis requires a high concentration of additive chemicals.

According to Rice, the new reactor requires less additive chemicals than the electrochemical synthesis, allowing nitrates to be converted more sustainably. The reactor relies on an innovative porous solid electrolyte as well as recyclable ions and a three-chamber system to improve the reaction’s efficiency.

Additionally, this development provides an effective water decontamination method.

“We conducted experiments where we flowed nitrate-contaminated water through this reactor and measured the amount of ammonia produced and the purity of the treated water,” Feng-Yang Chen, a Rice graduate student who is the lead author on the study, says. “We discovered that our novel reactor system could turn nitrate-contaminated water into pure ammonia and clean water very efficiently, without the need for extra chemicals. In simple terms, you put wastewater in, and you get pure ammonia and purified water out.”

Pedro Alvarez, the George R. Brown Professor of Civil and Environmental Engineering, director of the Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT) and the Water Technologies Entrepreneurship and Research (WaTER) Institute at Rice, says the reactor is "very timely and important" for growing cities that must deal with nitrate-contaminated groundwater supplies it.

"Conventional nitrate removal in drinking water treatment involves ion exchange or membrane filtration by reverse osmosis, which generates brines and transfers the nitrate problem from one phase to another,” he continues.

Wang's lab has been making headlines in recent years for innovative processes and technologies focused on the energy transition.

Last year, the lab published a study in Nature detailing a new technology that uses electricity to remove carbon dioxide from air capture to induce a water-and-oxygen-based electrochemical reaction, generating between 10 to 25 liters of high-purity carbon using only the power of a standard lightbulb.

In 2022, Rice reported that Wang’s lab in the George R. Brown School of Engineering had also replaced rare, expensive iridium with ruthenium, a more abundant precious metal, as the positive-electrode catalyst in a reactor that splits water into hydrogen and oxygen.

The lab received a portion of $10.8 million in research grants from the Houston-based Welch Foundation for research focused on converting carbon dioxide into useful chemicals, such as ethanol, last year. And Solidec, founded by Ryan Duchanois and Yang Xia from Wang's Lab, also received a $100,000 award from Rice as part of the One Small Step Grant program.

Wang has also been named among one of the most-cited researchers in the world.
Peng Zhu (left) and Haotian Wang developed a carbon-capture device prototype. Photos courtesy Jeff Fitlow/Rice University

Rice scientists develop simple but game-changing carbon capture device

small scale, big impact

A Rice University lab has developed an efficient, scalable way to capture carbon dioxide — and it just needs to be plugged into a power outlet to work.

The new technology developed in the lab of chemical and biomolecular engineer Haotian Wang, the William Marsh Rice Trustee Chair and an associate professor at Rice, uses electricity to remove carbon dioxide from air capture to induce a water-and-oxygen-based electrochemical reaction. The findings were shared in a study published in Nature last month.

Traditionally, carbon capture requires very energy intensive processes that need high temperatures and for the carbon that's been captured to be regenerated. The process also often requires large-scale infrastructure.

In the Wang lab's method, the small reactor can continuously remove carbon dioxide from a simulated flue gas with nearly 100 percent efficiency, generating between 10 to 25 liters of high-purity carbon using only the power of a standard lightbulb, according to a statement from Rice.

It does not create or consume chemicals, nor does it need to be heated up or pressurized, according to Wang. And it only requires a simple power source.

"The technology can be scaled up to industrial settings—power plants, chemical plants—but the great thing about it is that it allows for small-scale use as well: I can even use it in my office,” Wang says in the statement. “We could, for example, pull carbon dioxide from the atmosphere and continuously inject that concentrated gas into a greenhouse to stimulate plant growth. We’ve heard from space technology companies interested in using the device on space stations to remove the carbon dioxide astronauts exhale.”

Wang and lab member Peng Zhu, a chemical and biomolecular engineering graduate student at Rice and lead author on the study, initially made the discovery when working on an earlier version of the reactor intended for carbon dioxide utilization.

During this process Zhu noticed that gas bubbles flowed out of the reactor’s middle chamber when producing liquid products like acetic acid and formic acid, and that the number of bubbles would increase when more current was applied to the reactor.

This led the scientists to realize that the reactor was creating carbonate ions that were converted into a continuous flow of high-purity carbon dioxide after passing through the reactor's solid-electrolyte layer.

“Scientific discovery often requires this patient, continuous observation and the curiosity to learn what’s really going on, the choice not to neglect those phenomena that don’t necessarily fit in the experimental frame," Wang said in a statement.

A number of players in the Houston area have been making headway in carbon capture space in recent weeks.

Earlier this summer, the U.S. Department of Energy granted more than $45 million in federal funding to four Houston companies to promote the capture, transportation, use, and storage of tons of carbon dioxide emissions.

The Rice Alliance also recently named 15 startups to its Clean Energy Accelerator. A number of the fledgling companies are focused on carbon management and capture.

Video by Brandon Martin/Rice University

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Houston's Rhythm Energy expands nationally with clean power acquisition

power deal

Houston-based Rhythm Energy Inc. has acquired Inspire Clean Energy for an undisclosed amount. The deal allows Rhythm to immediately scale outside of Texas and into the Northeast, Midwest and mid-Atlantic regions, according to a release from the company.

Inspire offers subscription-based renewable electricity plans to customers in Pennsylvania, New York, New Jersey, Massachusetts, Ohio, Delaware, Illinois, Maryland, and Washington, D.C. By combining forces, Rhythm will now be one of the largest independent green-energy retailers in the country.

“Adding Inspire to the Rhythm family gives us the geographic reach to serve millions of new customers with the highly rated customer experience Texans already enjoy,” PJ Popovic, CEO of Rhythm, said in the release. “Together we become one of the largest independent green-energy retailers in the country and can roll out innovations like our PowerShift Time-of-Use plan and device-enabled demand-response programs that put customers fully in control of their energy costs.”

Rhythm was founded by Popovic in 2020 and offers 100 percent renewable energy plans using solar power, wind power and other renewable power sources.

In addition to scaling geographically, the acquisition will "(marry) Rhythm's data-driven technology with Inspire's successful subscription model." Rhythm also plans to upgrade its digital tools and provide more advanced services to help lower clean energy costs, according to the release.

Popovic spoke with EnergyCapital in 2023 about where he thinks renewables fit into Texas’s energy consumption. Read more here.

Fervo Energy lands $200 million in capital for new geothermal project

fresh funding

Houston-based Fervo Energy, a producer of geothermal power, has secured $205.6 million in capital to help finance its geothermal project in southern Utah.

The money will go toward the first and second phases of Cape Station, a geothermal energy plant being developed in Beaver County, Utah. Beaver County is roughly an equal distance between Salt Lake City and Las Vegas.

The $205.6 million in capital came from three sources:

  • $100 million in equity from Breakthrough Energy Catalyst, a Kirkland, Washington-based platform that invests in emissions-reducing projects.
  • $60 million addition to Fervo’s existing loan from Mercuria, a Swiss energy and commodities trader. The revolving loan now totals $100 million.
  • $45.6 million in additional bridge debt financing from XRL-ALC, an affiliate of Irvington, New York-based X-Caliber Rural Capital. X-Caliber is a USDA-approved lender. The initial bridge loan was $100 million.

The first phase of Cape Station will supply 100 megawatts of carbon-free electricity to the power grid starting next year. Another 400 megawatts of capacity is supposed to go online by 2028. Fervo has permission to expand Cape Station’s capacity to as much as 2 gigawatts. On an annual basis, 2 gigawatts can supply enough electricity to power about 1.4 million homes.

“These investments demonstrate what we’ve known all along: Fervo’s combination of technical excellence, commercial readiness, and market opportunity makes us a natural partner for serious energy capital. The confidence our investors have in Fervo and in the Cape asset affirms that next-generation geothermal is ready to play a defining role in America’s energy future,” David Ulrey, Fervo’s CFO, said in a news release.