Rice and UH scientists redefine chemical manufacturing method to solve carbon capture problem

Rice University

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Haotian Wang, associate professor in chemical and biomolecular engineering at the George R. Brown School of Engineering and Computing at Rice University (Credit: Jeff Fitlow/Rice University).

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Credit: Jeff Fitlow/Rice University

Each year billions of tons of carbon dioxide and other greenhouse gases are released into the atmosphere by the burning of fossil fuels, certain industrial processes, construction and other human activities, creating an urgent need to find better solutions to reduce the levels of atmospheric carbon dioxide.

A team of scientists led by Haotian Wang, associate professor in chemical and biomolecular engineering at the George R. Brown School of Engineering and Computing at Rice University, and Xiaonan Shan, associate professor of electrical and computer engineering at University of Houston, have discovered simple yet elegant solutions to address a fundamental issue in carbon capture and utilization technology — carbon dioxide reduction reaction (CO2RR). The study was published recently in Nature Energy.

“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. “The improvements we developed are crucial for transitioning CO 2 electrolysis from laboratory setups to commercial applications for producing sustainable fuels and chemicals.”

Salt buildup a major operational issue

CO2RR is a newly emerging carbon capture and utilization technique in which electricity — preferably generated by renewable sources like solar energy — and specific chemical catalysts are used to convert carbon dioxide gas into carbon-containing compounds like alcohols, ethylene, formic acids or carbon monoxide that can be used as fuels, chemicals or as starting materials to produce other compounds.

This technology is used in commercial membrane electrode assembly (MEA) electrolyzers to convert carbon dioxide into valuable compounds. However, this technology has one major setback: Over time, bicarbonate salt crystals accumulate on the backside of the cathode gas diffusion electrode and within the gas flow channels.

These salt precipitates block the flow of carbon dioxide gas through the cathode chamber, reducing the performance and causing the eventual failure of the electrolyzers.

“Operational instability is a big hurdle in the wider adoption of this technology,” Wang said. “The device functions normally for a few hundred hours after which it stops working due to the buildup of salt. Our goal in undertaking this study was to understand why and how bicarbonate salts form during this reaction, which we hoped would lead us to some preventive solutions that can extend the life of this device.”

Identifying the cause

One of the primary challenges was understanding the mechanism behind salt formation and migration within the MEA reactor, Shan said.

“Salt accumulation is problematic because it leads to the formation of bicarbonate salt particles in the gas diffusion electrode (GDE) and gas flow channels,” Shan said. “These precipitates block CO2diffusion pathways, impeding the flow of reactant gases to the catalyst sites, and could potentially damage the membrane of the reactor as well.”

To understand why these salt crystals form, Wang and his team at Rice collaborated with Shan and his team at UH who are experts in operando Raman spectroscopy, a powerful technique that allows researchers to study the structure of materials and any precipitates that adhere to it while the device is functioning.

“Our studies revealed that during this reaction, the microenvironment at the interface of the catalyst and anion electrode membrane is always alkaline,” Shan said. “This allows the hydroxide molecules to easily react with the acidic carbon dioxide molecules to form carbonate ions, which can then bind with the positively charged ions (cations) like sodium or potassium present there to form the bicarbonate salt deposits as they migrate towards the cathode.”

Finding solutions

The researchers’ next goal was to figure out ways to prevent these salt crystals from forming inside the gas flow channel.

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

The first idea they tested was whether lowering the concentration of cations like sodium or potassium in the electrolyte would slow down the salt formation.

Indeed, they found this was an effective solution. Reducing the concentration of the cations in the system prevented their crossover to the cathode, slowing down salt buildup and improving the reactor’s long-term functional stability.

“As we visualized this reaction using optical microscopy, we saw an interesting phenomenon. The bicarbonate crystals formed and remained trapped in droplets initially. With time, the droplets would evaporate leaving the salt crystals behind,” Wang said.

This simple but astute observation led them to think of another creative solution to solve the problem.

“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.

To test this idea, they coated the cathode gas flow channels of the MEA electrolyzer with parylene, a synthetic polymer like Teflon, that repels water. They found that parylene-coated gas channels flushed out substantially higher amounts of cations like potassium compared to a noncoated system, which notably improved the stability of the electrolyzer.

“Currently, salt-crusted electrodes and other affected components of the MEA electrolyzer need to be replaced after a few hundred hours of run time, but with our improvements, the functional stability of this device can be extended to more than 1,000 hours,” Wang said. “We are excited by this significant improvement in the device’s performance and life, and we believe that the easy scalability of these solutions to commercial applications will drive wider adoption of CO2RR technology as a means to manufacture chemicals and combat climate change.”

This work was supported by the Robert A. Welch Foundation, the David and Lucile Packard Foundation, the UL Research Institutes, a Department of Agriculture Small Business Innovation Research and Technology award and grants from the University Training and Research for Fossil Energy Applications and the Department of Defense’s Defense University Research Instrumentation Program.

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Journal

Nature Energy

DOI

10.1038/s41560-024-01695-4 

Article Title

Improving the operational stability of electrochemical CO2 reduction reaction via salt precipitation understanding and management

SDG*

University secures more than £500 thousand to tackle sustainability challenges in Jordan, the Philippines and Thailand

Aston University

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Dr Abed Alaswad, 

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Credit: Aston University

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• More than £500k secured to train early career researchers to boost sustainability 
• The University will host nine early career academics as part of the International Science Partnership Fund research fellowship programme
• Fellows from Jordan, Thailand and the Philippines will tackle sustainability challenges in their home countries.

An Aston University researcher has secured more than half a million pounds funding to train early career researchers to tackle sustainability challenges in their home countries.

The University will host nine early career academics for 12 months as part of the International Science Partnership Fund (ISPF) research fellowship programme. 

Fellows from Jordan will focus on energy systems, those from Thailand will work on sustainable plastics and green solvents and researchers from the Philippines will specialise in sustainability assessments.

The £540,000 grant was awarded to Dr Abed Alaswad, from the University’s Engineering for Sustainable Development Research Centre. The ISPF programme aims to equip emerging academics with the expertise needed to solve major sustainable development challenges. The fellows - three from each participating country - will undertake projects aligned with their respective national sustainability priorities while receiving industrial mentoring and support to help establish their careers.

Dr Alaswad will lead the programme and directly supervise the Jordan cohort, with Dr Vesna Najdanovic overseeing the Thai researchers and Professor Mirjam Roeder guiding the Philippine fellows.

He said: “This achievement further enhances Aston University’s global research footprint and fosters international collaborations, contributing to the University’s strategic ambitions of impactful global partnerships and empowering the next generation of research leaders.”

Dr Alaswad previously secured £180,000 under the same initiative to host three researchers from the Philippines, further demonstrating the University’s commitment to advancing sustainable development research worldwide.

*SUSTAINABLE DEVELOPMENT GOALS

 

Slow, silent ‘scream’ of epithelial cells detected for first time

Team from UMass Amherst uncovers communication by “electric spiking” in cells once thought to be mute, which could enable bioelectric applications

University of Massachusetts Amherst

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Granick and Yu used an epithelial-cell-coated chip with 60 precisely placed electrodes that could detect minute electric shifts.

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Credit: UMass Amherst

 

 

 

AMHERST, Mass. — It has long been thought that only nerve and heart cells use electric impulses to communicate, while epithelial cells — which compose the linings of our skin, organs and body cavities — are mute, serving mostly as protective barriers that can absorb and secrete various substances. But two researchers from the University of Massachusetts Amherst have upended the status quo by showing that epithelial cells do indeed “talk” to each other, albeit with slow electrical signals. Led by Steve Granick, Robert K. Barrett Professor of Polymer and Science and Engineering, and postdoctoral fellow Sun-Min Yu, the discovery, published recently in the Proceedings of the National Academy of Sciences, could enable new applications for everything from wearable bioelectric sensors to wound healing.

“Epithelial cells do things that no one has ever thought to look for,” says Granick. “When injured, they ‘scream’ to their neighbors, slowly, persistently and over surprising distances. It’s like a nerve’s impulse, but 1,000 times slower.” His team’s curiosity-driven approach, blending polymer science and biology, unveiled this hidden cellular signaling.

Granick and Yu used an epithelial-cell-coated chip with 60 precisely placed electrodes to eavesdrop. Yu, a cell-culture expert, grew a single layer of human epithelial cells on the chip, which detected minute electric shifts.

Using a precise laser to produce “sting” patterns of individual cells, they watched as signals rippled outward. “We tracked how cells coordinated their response,” Yu explained. “It’s a slow-motion, excited conversation.”

Unlike the swift neurotransmitter bursts of nerve cells, epithelial cells rely on ion flows — of calcium, especially — that produce signals that are far slower than those in nerve cells, but with similar voltages. These signals can be long-lived: Granick and Yu observed cells that “talked” for over five hours across distances nearly 40 times their own length.

Though Granick and Yu showed that calcium ions are necessary for epithelial conversation, they have yet to test what else might contribute to the conversation. And though the immediate applications of their new discovery remain to be seen, the implications are vast.

“Wearable sensors, implantable devices and faster wound healing could grow from this,” Granick noted. “Understanding these screams between wounded cells opens doors we didn’t know existed,” Yu added.

 

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2427123122 

Article Title

Electric spiking activity in epithelial cells

Article Publication Date

17-Mar-2025

Cuny.eduopenlab.citytech.cuny.edu/?get_group_doc=22694/1540157347-HarlanEllison-IHaveNoMouthandIMustScream.pdf

I Have No Mouth, and I Must Scream - City Tech OpenLab

I Have No Mouth, and I Must Scream by Harlan Ellison http://hermiene.net/shortstories/i_have_no_mouth.html. 1/11. I Have No Mouth, and I Must. Scream by Harlan ...

 

How big brains and flexible skulls led to the evolution of modern birds

3D modeling shows how larger brains triggered changes in jaw muscles and joint mechanics that powered a flexible feeding system for modern birds.

University of Chicago

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Comparison of bird, reptile, and dinosaur skulls

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Credit: Alec Wilken, Casey Holiday

Modern birds are the living relatives of dinosaurs. Take a look at the features of flightless birds like chickens and ostriches that walk upright on two hind legs, or predators like eagles and hawks with their sharp talons and keen eyesight, and the similarities to small theropod dinosaurs like the velociraptors of Jurassic Park fame are striking.

Yet birds differ from their reptile ancestors in many important ways. A turning point in their evolution was the development of larger brains, which in turn led to changes in the size and shape of their skulls.

New research from the University of Chicago and University of Missouri shows how these physical changes affected the mechanics of the way birds move and use their beaks to eat and explore their habitats — adaptations that helped them evolve into the extraordinarily diverse winged creatures we see today.

The benefits of ‘wiggly’ skulls

Modern birds, as well as other animals like snakes and fishes, have skulls with jaws and palates that aren’t rigid and fixed in place like those in mammals, turtles, or non-avian dinosaurs. Alec Wilken, a graduate student in integrative biology at UChicago and lead author of the new study, calls this kind of flexible skull “wiggly.” He says this characteristic makes it that much harder to figure out how the pieces work together.

“Just because you have a joint there, that doesn't mean that you know how it moves,” Wilken said. “So, you also have to think about how muscles are going to be pulling on the joint, what kind of torque they have, and how other joints in the head limit the mobility.”

Wilken joined the project in 2015 when he was an undergraduate at the University of Missouri. Casey Holliday, PhD, Associate Professor of Pathology and Anatomical Sciences at University of Missouri, received a grant from the National Science Foundation (NSF) to study how the skulls, jaw muscles, and feeding mechanics changed along the transition from dinosaurs to birds, and Wilken joined his lab to help.

The team began by taking CT scans of a variety of fossils and skeletons from modern-day birds and related reptiles like alligators. Using the data from these images, they then built 3D models to calculate the mechanics of the skulls and jaws in action — muscle sizes and placements, their movements, and the physics involved in how they all fit together.

One of the key differences between modern birds and other animals is that they have what’s called “cranial kinesis”: the ability to move different parts of the skull independently. This gives birds an evolutionary advantage by literally expanding their palates to eat different kinds of foods or use their beaks as a multifunctional tool.

“Having a wiggly head like this really gives them a lot of evolutionary benefits,” Wilken said. Parrots, for example, can use their beaks to help climb; the extra torque helps other birds crack nuts and seeds. “In some ways, the beak functions like a surrogate hand, but being able to move the palate around while eating is also mission critical to helping them acquire food and survive.”

A cascade of changes from dinosaurs to birds

When the team analyzed data from the 3D models, they saw that as brain and skull sizes increased in non-avian theropod dinosaurs, muscles shifted into different positions that allowed the palate to separate and become mobile. These changes in turn increased muscle force, which powers cranial kinesis in most modern-day birds.

“We see this cascade of changes that happened along the dinosaur to bird transition,” Holliday said. “A large part of it hinges upon when birds evolved a relatively large brain. Just like in humans, bigger brains drive a lot of changes in the skull.”

As paleontologists discover more details about dinosaurs, the dividing line between them and modern birds becomes murky (yes, birds are technically dinosaurs, but we’re speaking in broad terms here). Scientists used to think feathers were the key, but now we know that many bona fide dinosaurs had feathers too. Flight also evolved more than once, and of course many well-known, classic dinos could fly as well.

However, flexible skulls and palates appeared later than transitional dinosaur/bird creatures like Archaeopteryx, and Holliday thinks that may become a key distinction. “Cranial kinesis might be one of the clear dividing lines between modern birds and their more dinosaur-like bird ancestors.”

 

The study, “Avian cranial kinesis is the result of increased encephalization during the origin of birds,” was published in the Proceedings of the National Academy of Sciences. Additional authors include Kaleb C. Sellers from UChicago, Ian N. Cost from Albright College, Jul Davis from the University of Southern Indiana, Kevin M. Middleton from the University of Missouri, and Lawrence M. Witmer from Ohio University.

Theropod skull - vertical [VIDEO] | EurekAlert! Science News Releases

Bird skull - vertical [VIDEO] | EurekAlert! Science News Releases

Theropod skull - horizontal [VIDEO] | EurekAlert! Science News Releases

Bird skull - horizontal [VIDEO] | EurekAlert! Science News Releases

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2411138122 

Method of Research

Imaging analysis

Subject of Research

Animals

Article Title

Avian cranial kinesis is the result of increased encephalization during the origin of birds

Article Publication Date

17-Mar-2025

 

Iguanas floated one-fifth of the way around the world to colonize Fiji

The voyage, the longest known transatlantic dispersal of any land animal, took place within the last 34 million years

University of California - Berkeley

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A Fijian crested iguana (Brachylophus vitiensis) resting on a coconut palm on the island of Fiji in the South Pacific. The four species of iguanas that inhabit Fiji and Tonga today are descended from ancestors that colonized the island within the past 34 million years, probably by rafting 5,000 miles across the Pacific Ocean from western North America.

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Credit: Nicholas Hess

Iguanas have often been spotted rafting around the Caribbean on vegetation and, ages ago, evidently caught a 600-mile ride from Central America to colonize the Galapagos Islands. But for long distance travel, the Fiji iguanas can't be touched.

A new analysis conducted by biologists at the University of California, Berkeley, and the University of San Francisco (USF) suggests that sometime after about 34 million years ago, Fiji iguanas landed on the isolated group of South Pacific islands after voyaging 5,000 miles from the western coast of North America — the longest known transoceanic dispersal of any terrestrial vertebrate.

Overwater dispersal is the main way newly formed islands get populated by plants and animals, including humans, often leading to the evolution of new species and entirely new ecosystems. Understanding how these colonizations happen has fascinated scientists since the time of Charles Darwin, the originator of the theory of evolution by natural selection.

The new analysis, to be published next week in the journal Proceedings of the National Academy of Sciences, suggests that the arrival of the ancestors of the Fiji iguanas coincided with the formation of these volcanic islands. The estimated time of the arrival, 34 million years ago or more recently, is based on the timing of the genetic divergence of the Fiji iguanas, Brachylophus, from their closest relatives, the North American desert iguanas, Dipsosaurus.

Previously, biologists had proposed that Fiji iguanas may have descended from an older lineage that was more widespread around the Pacific but has since died out, leaving Brachylophus as the sole iguanids in the western Pacific Ocean. Another option was that the iguanas hitchhiked from tropical parts of South America and then through Antarctica or even Australia, though there is no genetic or fossil evidence to support this.

The new analysis puts those theories to rest.

"We found that the Fiji iguanas are most closely related to the North American desert iguanas, something that hadn't been figured out before, and that the lineage of Fiji iguanas split from their sister lineage relatively recently, much closer to 30 million years ago, either post-dating or at about the same time that there was volcanic activity that could have produced land," said lead author Simon Scarpetta, a herpetologist and paleontologist who is a former postdoctoral fellow at  UC Berkeley and is now an assistant professor at USF in the Department of Environmental Science.

"That they reached Fiji directly from North America seems crazy," said co-author Jimmy McGuire, UC Berkeley professor of integrative biology and herpetology curator at the Museum of Vertebrate Zoology. "But alternative models involving colonization from adjacent land areas don’t really work for the time frame, since we know that they arrived in Fiji within the last 34 million years or so. This suggests that as soon as land appeared where Fiji now resides, these iguanas may have colonized it. Regardless of the actual timing of dispersal, the event itself was spectacular."

While sailors today can take advantage of favorable winds to reach Fiji from California in about a month, an iguana — or more likely a group of iguanas — would probably have taken much longer to ride flotsam through the doldrums and across the equator to Fiji and Tonga, where this group of iguanas is found. Luckily, iguanas are large and herbivorous and used to long periods without food and water. And if the flotsam consisted of uprooted trees, the raft itself would have provided food.

"You could imagine some kind of cyclone knocking over trees where there were a bunch of iguanas and maybe their eggs, and then they caught the ocean currents and rafted over," Scarpetta said.

The Fiji iguanas are an outlier

All told, there are over 2,100 species in the suborder Iguania, a large group that also includes animals such as chameleons, anoles, bearded dragons and horned lizards. What most people think of as iguanas are the Western Hemisphere family of lizards, Iguanidae, that include and mostly look like the widespread green iguana of Central and South America that Carl Linnaeus described as Iguana iguana in 1758. There are 45 species of Iguanidae living in the Caribbean and the tropical, subtropical and desert areas of North, Central and South America. These include the well-known marine iguanas of the Galapagos Islands, but also the chuckwallas of the American Southwest.

The Fiji iguanas are an outlier, sitting all alone in the middle of the Pacific. The four species on Fiji and Tonga are listed as endangered, primarily because of habitat loss, predation by invasive rats and exploitation by smugglers feeding the exotic pet trade.

Biologists had speculated, based on a few fossils found in east Asia, that an ancestral population of iguanids, now extinct, lived around the Pacific Rim and somehow made their way to the middle of the Pacific, island-hopping along the way. They may have journeyed by land and sea from America via the Bering Land Bridge and on through Indonesia and Australia or down along the Pacific coast of the Americas and through Antarctica. Or they could have rafted from South America with the Humboldt Current, gyring into the South Pacific.

Previous genetic analyses of a few genes for iguanid lizards were inconclusive about the relationship of the Fiji iguanas to all the rest. Scarpetta, while a postdoctoral fellow with McGuire a few years ago, embarked on a comprehensive survey of all genera in the Iguania to clarify the family tree of the group.

"Different relationships have been inferred in these various analyses, none with particularly strong support," McGuire said. "So there was still this uncertainty about where Brachylophus really fits within the iguanid phylogeny. Simon's data really nailed this thing."

Scarpetta collected genome-wide sequence DNA from more than 4,000 genes and from tissues of more than 200 iguanian specimens housed in museum collections around the world. As he began comparing these data, one result stood out clearly: The Fiji iguanas are most closely related to the iguanas in the genus Dipsosaurus. The most widespread of these is the North American desert iguana, Dipsosaurus dorsalis, which is adapted to the searing heat of the deserts of the American Southwest and northern Mexico. The other species in the genus is native to Santa Catalina Island in the Sea of Cortez.

"Iguanas and desert iguanas, in particular, are resistant to starvation and dehydration, so my thought process is, if there had to be any group of vertebrate or any group of lizard that really could make an 8,000 kilometer journey across the Pacific on a mass of vegetation, a desert iguana-like ancestor would be the one," Scarpetta said.

The analysis determined that the two lineages, Brachylophus and Dipsosaurus, diverged about 34 million years ago, which doesn't fit with earlier theories of the origin of the Fiji iguanas.

"When you don't really know where Brachylophus fits at the base of the tree, then where they came from can also be almost anywhere," McGuire said. "So it was much easier to imagine that Brachylophus originated from South America, since we already have marine and land iguanas in the Galapagos that almost certainly dispersed to the islands from the mainland."

With the new analysis, a South American origin can be ruled out. And because the Fiji Islands emerged from the sea also about 34 million years ago, the iguanas may have serendipitously intersected the islands not long after. Other islands aside from Fiji and Tonga could also have harbored iguanas, Scarpetta noted, but it is the nature of volcanic islands to disappear as readily as they appear. Evidence of other Pacific Island iguanas, if they existed, has probably been lost.

Scarpetta, who has been enamored with salamanders, snakes and lizards since before high school, continues to analyze genome-wide data for Iguanian lizards to learn more about their evolutionary relationships and to infer their movements and interactions through time and space.

Other co-authors of the paper are Robert Fisher of the U.S. Geological Survey in San Diego, Benjamin Karin and Ammon Corl of UC Berkeley, Jone Niukula of NatureFiji-MareqetiViti in Suva and Todd Jackman of Villanova University in Pennsylvania. Scarpetta was supported by a National Science Foundation postdoctoral research fellowship.

A male Central Fijian banded iguana, Brachylophus bulabula, from Ovalau Island, Fiji.

Credit

USGS

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2318622122 

Subject of Research

Animals

Article Title

Iguanas rafted more than 8,000 km from North America to Fiji

Article Publication Date

17-Mar-2025