Science
How a Record-Breaking Copper Catalyst Converts CO2 Into Liquid Fuels
Researchers at Berkeley Lab have made real-time movies of copper nanoparticles as they evolve to convert carbon dioxide and water into renewable fuels and chemicals. Their new insights could help advance the next generation of solar fuels
Video of a 4D-STEM experiment: Berkeley Lab researchers used a new electrochemical liquid cell to observe copper nanoparticles (ranging in size from 7 nanometers to 18 nanometers) evolve into active nanograins during CO2 electrolysis – a process that uses electricity to drive a reaction on the surface of an electrocatalyst. The new electrochemical liquid cell allows researchers to resolve images of objects smaller than 10 nanometers.
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Newswise — Since the 1970s, scientists have known that copper has a special ability to transform carbon dioxide into valuable chemicals and fuels. But for many years, scientists have struggled to understand how this common metal works as an electrocatalyst, a mechanism that uses energy from electrons to chemically transform molecules into different products.
Now, a research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has gained new insight by capturing real-time movies of copper nanoparticles (copper particles engineered at the scale of a billionth of a meter) as they convert CO2 and water into renewable fuels and chemicals: ethylene, ethanol, and propanol, among others. The work was reported in the journal Nature last week.
“This is very exciting. After decades of work, we’re finally able to show – with undeniable proof – how copper electrocatalysts excel in CO2 reduction,” said Peidong Yang, a senior faculty scientist in Berkeley Lab’s Materials Sciences and Chemical Sciences Divisions who led the study. Yang is also a professor of chemistry and materials science and engineering at UC Berkeley. “Knowing how copper is such an excellent electrocatalyst brings us steps closer to turning CO2 into new, renewable solar fuels through artificial photosynthesis.”
The work was made possible by combining a new imaging technique called operando 4D electrochemical liquid-cell STEM (scanning transmission electron microscopy) with a soft X-ray probe to investigate the same sample environment: copper nanoparticles in liquid. First author Yao Yang, a UC Berkeley Miller postdoctoral fellow, conceived the groundbreaking approach under the guidance of Peidong Yang while working toward his Ph.D. in chemistry at Cornell University.
Credit: Thor Swift/Berkeley Lab
(From left to right): Julian Feijoo, Jianbo Jin, Cheng Wang, Peidong Yang, Yao Yang, Inwhan Roh, and Maria Fonseca Guzman at the Advanced Light Source.
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Artist’s rendering of a copper nanoparticle as it evolves during CO2 electrolysis: Copper nanoparticles (left) combine into larger metallic copper “nanograins” (right) within seconds of the electrochemical reaction, reducing CO2 into new multicarbon products.
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Credit: Thor Swift/Berkeley Lab
Yao Yang (center) loads a sample into the soft X-ray scattering chamber as Cheng Wang (left) and Peidong Yang (right) observe at the RSoXS Beamline (Beamline 11.0.1.2) at the Advanced Light Source.
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Scientists who study artificial photosynthesis materials and reactions have wanted to combine the power of an electron probe with X-rays, but the two techniques typically can’t be performed by the same instrument.
Electron microscopes (such as STEM or TEM) use beams of electrons and excel at characterizing the atomic structure in parts of a material. In recent years, 4D STEM (or “2D raster of 2D diffraction patterns using scanning transmission electron microscopy”) instruments, such as those at Berkeley Lab’s Molecular Foundry, have pushed the boundaries of electron microscopy even further, enabling scientists to map out atomic or molecular regions in a variety of materials, from hard metallic glass to soft, flexible films.
On the other hand, soft (or lower-energy) X-rays are useful for identifying and tracking chemical reactions in real time in an operando, or real-world, environment.
But now, scientists can have the best of both worlds. At the heart of the new technique is an electrochemical “liquid cell” sample holder with remarkable versatility. A thousand times thinner than a human hair, the device is compatible with both STEM and X-ray instruments.
The electrochemical liquid cell’s ultrathin design allows reliable imaging of delicate samples while protecting them from electron beam damage. A special electrode custom-designed by co-author Cheng Wang, a staff scientist at Berkeley Lab’s Advanced Light Source, enabled the team to conduct X-ray experiments with the electrochemical liquid cell. Combining the two allows researchers to comprehensively characterize electrochemical reactions in real time and at the nanoscale.
Getting granular
During 4D-STEM experiments, Yao Yang and team used the new electrochemical liquid cell to observe copper nanoparticles (ranging in size from 7 nanometers to 18 nanometers) evolve into active nanograins during CO2 electrolysis – a process that uses electricity to drive a reaction on the surface of an electrocatalyst.
The experiments revealed a surprise: copper nanoparticles combined into larger metallic copper “nanograins” within seconds of the electrochemical reaction.
To learn more, the team turned to Wang, who pioneered a technique known as “resonant soft X-ray scattering (RSoXS) for soft materials,” at the Advanced Light Source more than 10 years ago.
With help from Wang, the research team used the same electrochemical liquid cell, but this time during RSoXS experiments, to determine whether copper nanograins facilitate CO2 reduction. Soft X-rays are ideal for studying how copper electrocatalysts evolve during CO2 reduction, Wang explained. By using RSoXS, researchers can monitor multiple reactions between thousands of nanoparticles in real time, and accurately identify chemical reactants and products.
The RSoXS experiments at the Advanced Light Source – along with additional evidence gathered at Cornell High Energy Synchrotron Source (CHESS) – proved that metallic copper nanograins serve as active sites for CO2 reduction. (Metallic copper, also known as copper(0), is a form of the element copper.)
During CO2 electrolysis, the copper nanoparticles change their structure during a process called “electrochemical scrambling.” The copper nanoparticles’ surface layer of oxide degrades, creating open sites on the copper surface for CO2 molecules to attach, explained Peidong Yang. And as CO2 “docks” or binds to the copper nanograin surface, electrons are then transferred to CO2, causing a reaction that simultaneously produces ethylene, ethanol, and propanol along with other multicarbon products.
“The copper nanograins essentially turn into little chemical manufacturing factories,” Yao Yang said.
Further experiments at the Molecular Foundry, the Advanced Light Source, and CHESS revealed that size matters. All of the 7-nanometer copper nanoparticles participated in CO2 reduction, whereas the larger nanoparticles did not. In addition, the team learned that only metallic copper can efficiently reduce CO2 into multicarbon products. The findings have implications for “rationally designing efficient CO2 electrocatalysts,” Peidong Yang said.
The new study also validated Peidong Yang’s findings from 2017: That the 7-nanometer-sized copper nanoparticles require low inputs of energy to start CO2 reduction. As an electrocatalyst, the 7-nanometer copper nanoparticles required a record-low driving force that is about 300 millivolts less than typical bulk copper electrocatalysts. The best-performing catalysts that produce multicarbon products from CO2 typically operate at high driving force of 1 volt.
The copper nanograins could potentially boost the energy efficiency and productivity of some catalysts designed for artificial photosynthesis, a field of research that aims to produce solar fuels from sunlight, water, and CO2. Currently, researchers within the Department of Energy-funded Liquid Sunlight Alliance (LiSA) plan to use the copper nanograin catalysts in the design of future solar fuel devices.
“The technique’s ability to record real-time movies of a chemical process opens up exciting opportunities to study many other electrochemical energy conversion processes. It’s a huge breakthrough, and it would not have been possible without Yao and his pioneering work,” Peidong Yang said.
Researchers from Berkeley Lab, UC Berkeley, and Cornell University contributed to the work. Other authors on the paper include co-first authors Sheena Louisa and Sunmoon Yu, former UC Berkeley Ph.D. students in Peidong Yang’s group, along with Jianbo Jin, Inwhan Roh, Chubai Chen, Maria V. Fonseca Guzman, Julian Feijóo, Peng-Cheng Chen, Hongsen Wang, Christopher Pollock, Xin Huang, Yu-Tsuan Shao, Cheng Wang, David A. Muller, and Héctor D. Abruña.
Parts of the experiments were performed by Yao Yang at Cornell under the supervision of Héctor Abruña, professor of chemistry and chemical biology, and David A. Muller, professor of engineering.
This work was supported by the DOE Office of Science.
The Molecular Foundry and Advanced Light Source are user facilities at Berkeley Lab.
Source: Lawrence Berkeley National Laboratory
News
Joby Aviation and Toyota kick off manufacturing alliance to scale electric air taxi production
Joby Aviation and Toyota launch a joint venture to improve productivity, quality, and cost as they prepare to scale electric air taxi production.
Joby Aviation and Toyota Motor Corporation have launched the initial phase of a strategic manufacturing alliance aimed at accelerating commercial production of electric air taxis—an early step the companies say is designed to make “air mobility for all” a practical, everyday reality.
Announced June 30, 2026, the partnership formalizes a new joint venture that will combine Joby’s electric aviation development with Toyota’s production systems and operational expertise. The near-term focus: building the groundwork for commercial production while pushing improvements in productivity, quality, and cost—key factors as the industry moves from prototypes to scaled manufacturing.
What the joint venture is designed to do
According to the companies, the alliance will initially concentrate on:
- Establishing the foundation for commercial production capability
- Advancing manufacturing excellence with an emphasis on productivity, quality, and cost
- Supporting expansion of Joby’s production capacity as it works toward aircraft certification and prepares for anticipated demand
The announcement positions Toyota’s manufacturing playbook—known globally for lean production and continuous improvement—as a lever to help Joby move from development into repeatable, high-quality output at scale.
Why it matters: eVTOLs need scale, not just flight tests
Electric vertical take-off and landing (eVTOL) aircraft have become one of the most closely watched bets in next-generation transportation, but the path to viable air taxi services depends on more than successful test flights. Certification timelines, supply chain readiness, and the ability to produce aircraft consistently (and affordably) are often what separates promising technology from commercial reality.
By forming a joint venture focused on manufacturing readiness, Joby and Toyota are signaling that the next competitive frontier is industrialization—how quickly and reliably eVTOL aircraft can be built to meet safety standards and market demand.
Related Links for Further reading
- Joby Aviation (official): https://www.jobyaviation.com
- Joby Investor Relations / News (official updates & filings): https://ir.jobyaviation.com
- Toyota Newsroom (official): https://www.toyotanewsroom.com
- Toyota Global (corporate overview): https://global.toyota/en
- FAA Advanced Air Mobility / Air Taxis (context): https://www.faa.gov/air-taxis
What executives are saying
Joby founder and CEO JoeBen Bevirt emphasized the long-running relationship between the companies, calling the joint venture a reflection of shared confidence in the opportunity ahead.
“Toyota has been by Joby’s side for nearly a decade, providing invaluable guidance and support as we built the foundation for manufacturing our aircraft,” Bevirt said. “Together, we share a vision of making aerial mobility an everyday reality.”
Toyota Motor Corporation Chairman Akio Toyoda framed air mobility as an extension of the company’s broader mission.
“Since our founding, we’ve been guided by the philosophy of providing mobility for all,” Toyoda said, adding that Toyota views air mobility as “a natural extension of that philosophy—from the ground into the sky.”
About the companies
Joby Aviation (NYSE: JOBY) is a California-based transportation company developing an all-electric eVTOL air taxi. The company intends to operate its own air taxi service in cities worldwide and sell aircraft to other operators and partners.
Toyota (NYSE: TM) has operated in North America for nearly 70 years and says it is focused on sustainable, next-generation mobility through Toyota and Lexus brands. Toyota reports nearly 64,000 employees in North America, 14 manufacturing plants, and more than 1,800 dealerships. The company also noted that its North Carolina plant began assembling automotive batteries for electrified vehicles in 2025.
What to watch for next
For readers tracking the air taxi sector, the next milestones will likely center on:
- Details on how the joint venture will be structured operationally
- Updates on Joby’s certification progress and production ramp timelines
- Signs of how manufacturing improvements translate into cost reductions and throughput
- Additional agreements or expanded collaboration as the alliance progresses
While the companies highlighted expected benefits, they also noted the usual forward-looking risks—such as regulatory certification timelines, market conditions, and the ability to finalize additional agreements.
Source: Toyota Motor North America / PRNewswire (June 30, 2026)
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STM Blog
From Hand Signals to Smart Crosswalks: The Evolution of the Modern Pedestrian Signal
Discover the history of the modern pedestrian signal, from Garrett A. Morgan’s groundbreaking traffic signal to today’s smart, accessible crosswalks.
Last Updated on July 12, 2026 by Daily News Staff
Every day, millions of people rely on pedestrian signals to cross busy street safely. A glowing white walking figure, an orange-red hand, and a countdown timer have become familiar sights around the world. While these signals may seem like simple pieces of infrastructure, they are the result of more than a century of innovation, engineering, and public safety improvements.
The modern pedestrian signal did not appear overnight. Instead, it evolved through the contributions of inventors, engineers, city planners, and transportation officials who continually refined traffic control systems as cities grew and automobiles became more common.
The Early Days of Traffic Control
Before electric traffic signals, intersections were controlled by police officers, railway-style semaphores, or even hand signals. As horse-drawn wagons gave way to automobiles in the early 1900s, traffic congestion and accidents increased dramatically, creating an urgent need for better traffic management.
One of the earliest electric traffic lights was installed in Cleveland, Ohio, in 1914. It used red and green lights and was manually operated. While it improved vehicle movement, pedestrians still had to judge for themselves when it was safe to cross.
Garrett A. Morgan’s Breakthrough
One of the most important milestones came in 1923 when inventor and entrepreneur Garrett Augustus Morgan received U.S. Patent No. 1,475,024 for an improved traffic signal.
Morgan’s design introduced a third position in addition to “Stop” and “Go.” This intermediate phase temporarily stopped traffic in every direction before allowing vehicles to proceed. The brief pause reduced confusion at intersections and provided additional time for pedestrians to cross safely.
Morgan reportedly developed his design after witnessing a serious traffic accident. His invention demonstrated how thoughtful engineering could improve public safety while making increasingly busy streets more efficient.
Although Morgan did not invent the illuminated “WALK” and “DON’T WALK” pedestrian signal used today, his three-position signal became a foundational step in the evolution of modern traffic control.
The Birth of Dedicated Pedestrian Signals
As cities expanded after World War II, pedestrian safety became an even greater concern. More people were walking in increasingly crowded downtown districts, and separating pedestrian movements from vehicle traffic became a priority.
During the early 1950s, several American cities began experimenting with dedicated pedestrian signals. New York City became one of the first major municipalities to install illuminated “WALK” and “DON’T WALK” signs at busy intersections.
These early systems gave pedestrians their own designated crossing phase, reducing conflicts with turning vehicles and improving safety at some of the nation’s busiest intersections.
Standardization Across America
By the 1960s and 1970s, traffic engineers recognized the importance of creating consistent traffic control devices nationwide.
The Manual on Uniform Traffic Control Devices (MUTCD) established national standards for traffic signs, pavement markings, and pedestrian signals. Standardized designs helped ensure that pedestrians could understand crossing signals regardless of where they traveled in the United States.
Eventually, words gave way to internationally recognized symbols—a walking person to indicate it was safe to cross and an upraised hand to indicate pedestrians should wait. These symbols transcended language barriers and improved accessibility for visitors and non-English speakers.
The Countdown Era
One of the most significant modern improvements arrived with pedestrian countdown timers.
Rather than simply flashing a warning, countdown displays show exactly how many seconds remain before the crossing phase ends. Research has shown that countdown timers help pedestrians make better crossing decisions and improve compliance with traffic signals.
Today, countdown timers have become standard equipment at intersections across much of the United States.
Accessibility Takes Center Stage
Modern pedestrian signals are designed to serve everyone.
Accessible Pedestrian Signals (APS) now provide audible tones, spoken messages, vibrating push buttons, and locator sounds that assist pedestrians who are blind or have low vision. These features allow more people to navigate intersections independently and safely.
The continued development of accessible technology reflects a broader commitment to making transportation systems inclusive for all users.
The Future of Pedestrian Safety
Pedestrian signals continue to evolve.
Many cities now use smart traffic systems that detect pedestrians waiting to cross, automatically adjust signal timing based on traffic conditions, and prioritize people walking during busy periods.
Researchers are exploring artificial intelligence, connected vehicle technology, and sensor-based systems capable of communicating directly with autonomous vehicles. Future pedestrian crossings may adapt in real time to weather conditions, crowd sizes, emergency vehicles, and even the needs of older adults or individuals with disabilities.
A Legacy Built by Many Innovators
The pedestrian signal we know today is the product of more than a century of collaboration and innovation.
Early traffic engineers created the first electric traffic lights. Garrett A. Morgan improved intersection safety with his groundbreaking three-position traffic signal. Transportation agencies standardized traffic control devices, while engineers continued refining pedestrian technology through countdown timers, accessible features, and intelligent traffic systems.
Every safe crossing today reflects the work of countless inventors, planners, researchers, and public officials dedicated to protecting lives.
As cities continue to grow and transportation technology advances, the humble pedestrian signal remains one of the most effective—and often overlooked—public safety innovations ever developed.
At STM Daily News, we celebrate the inventors, engineers, and visionaries whose everyday innovations quietly improve life for millions of people. Sometimes the most important inventions aren’t the ones that grab headlines—they’re the ones we depend on every single day without giving them a second thought.
Related Reading
- Federal Highway Administration – Manual on Uniform Traffic Control Devices (MUTCD)
- National Museum of African American History and Culture – Garrett Augustus Morgan
- United States Patent and Trademark Office
- Federal Highway Administration – Accessible Pedestrian Signals
- National Highway Traffic Safety Administration (NHTSA)
🧠 Discover the remarkable innovators, inventors, and trailblazers who helped shape our world but rarely receive the recognition they deserve. Share your thoughts in the comments and subscribe to the STM Daily News newsletter to catch every new Forgotten Genius Friday feature and more inspiring stories delivered to your inbox.
The Earth
Cement has a climate problem — here’s how geopolymers with add‑ins like cork could help fix it
Portland cement drives ~8% of global emissions. Learn how low-carbon geopolymers—enhanced with add-ins like cork—could cut concrete’s footprint.
Alcina Johnson Sudagar, Washington University in St. Louis
Concrete is all around you – in the foundation of your home, the bridges you drive over, the sidewalks and buildings of cities. It is often described as the second-most used material by volume on Earth after water.
But the way concrete is made today also makes it a major contributor to climate change.
Portland cement, the key component of concrete, is responsible for about 8% of global greenhouse gas emissions. That’s because it’s made by heating limestone to high temperatures, a process that burns a large amount of fossil fuels for energy and releases carbon dioxide from the limestone in the process.
The good news is that there are alternatives, and they are gaining attention.
Portland cement: A greenhouse gas problem
Cementlike substances have been used in construction for thousands of years. Architects have found evidence of their use in the pyramids of Egypt and the buildings and aqueducts of the Roman Empire.
The Portland cement commonly used in construction today was patented in 1824 by Joseph Aspdin, a British bricklayer.
Modern cement preparation starts with crushing the excavated raw materials limestone and clay and then heating them in a kiln at around 2,650 degrees Fahrenheit (about 1,450 degrees Celsius) to form clinker, a hard, rocklike residue. The clinker is then cooled and ground with gypsum into a fine powder, which is called cement.
About 40% of the carbon dioxide emissions from cement production come from burning fossil fuels to generate the high heat needed to run the kiln. The rest come as the heat converts limestone (calcium carbonate) to lime (calcium oxide), releasing carbon dioxide.
In all, between half a ton and 1 ton of greenhouse gas is released per ton of Portland cement. Cement is a binding agent that, mixed with water, holds aggregate together to create concrete. It makes up about 10% to 15% of the concrete mix by weight.
Alternative technologies can lower emissions
As populations, cities and the need for new infrastructure expand, the use of cement is growing, making it important to find alternatives with lower environmental costs.
Some techniques for reducing carbon dioxide emissions include substituting some of the clinker – the hard residue typically made from limestone – with supplementary materials such as clay, or fly ash and slag from industries. Other methods reduce the amount of cement by mixing in waste sawdust or recycled materials like plastics.
The long-term solution for reducing cement’s emissions, however, is to replace traditional cement completely with alternatives. One option is geopolymers made from earthen clay and industrial wastes.
Geopolymers: A more climate-friendly solution
Geopolymers can be made by mixing claylike materials that are rich in aluminum and silicon minerals with a chemical activator through a process called geopolymerization. The activator transforms the silicon and aluminum into a structure that will look like cement. All of this can happen at room temperature.
The major difference between cement and geopolymer is that cement is mainly made of calcium, whereas geopolymers are made of silicon and aluminum with some possible calcium in their structure.
These geopolymers have been found to possess high strength and durability, including resilience in freeze-thaw cycles and resistance to heat and fire, which are important requirements in construction. Studies have found that some geopolymers can provide comparable if not better strength than traditional cement and, because they don’t require heat the way clinker does, they can be produced with significantly lower greenhouse gas emissions.
Geopolymers can also be produced from a variety of raw materials rich in aluminum and silicon, including earthen clays, fly ash, blast furnace slag, rice husk ash, iron ore wastes and recycled construction brick waste. Geopolymer technology can be adapted depending on the clay or industrial waste locally available in a region. https://www.youtube.com/embed/NOj3p6m9M7Q?wmode=transparent&start=0 A brief history of cement and geopolymers. Geopolymer International.
An added advantage of geopolymers is that changes to the mixture can produce a range of features.
For example, I and my co-researchers at the University of Aveiro in Portugal added a small amount of cork industry waste – the leftovers from creating bottle corks – to clay-based geopolymer and found it could improve the strength of the material by up to twofold. The cork particles filled the spaces in the geopolymer structure, making it denser, which increased the strength.
Similarly, additives such as sisal fibers from the agave plant, recycled plastic and steel fibers can change geopolymer properties. The additives do not participate in the geopolymerization process but act as fillers in the structure.
The structure of geopolymers can also be designed to act as adsorbents, attracting toxic metals in wastewater and capturing and storing radioactive wastes. Specifically, incorporating materials like zeolite that are natural adsorbents in the geopolymer structure can make them useful for such applications as well.
Where geopolymers are used now
Geopolymers have been used in many types of construction, including roads, coatings, 3D printing, coastal environmental protection, the steel and chemical industries, sewer rehabilitation and building radiation shielding and rocket launchpad and bunker infrastructure.
One of the earliest examples of a modern geopolymer concrete project was the Brisbane West Wellcamp airport in Australia.
It was built in 2014 with 70,000 metric tons of geopolymer concrete, which was estimated to have reduced the project’s carbon dioxide emissions by as much as 80%.
The geopolymer market is currently estimated to be between US$7 billion and $10 billion, with the largest growth in the Asia-Pacific region.
Analysts have estimated that the market could grow at a rate of 10% to 20% per year and reach about $62 billion by 2033.
In several countries, greenhouse gas regulations and green-building certifications are expected to support the continued growth of geopolymers in the construction industry.
Expanding the use of cement alternatives
The advantage of using industrial wastes in geopolymers is a double-edged sword, however. The composition of industrial wastes varies, so it can be difficult to standardize the processing methods. The geopolymer components need to be mixed in particular ratios to achieve desired properties.
Producing the activator for the geopolymer, typically done in chemical facilities, can raise the cost and contribute to the carbon footprint. And the long-term data about these materials’ stability is only now being developed given their newness. Also, these geopolymers can take longer to set than cement, though the setting time can be sped up by using raw materials that react quickly.
Developing cheaper, naturally available activators like agricultural waste rice husk with sustainable supply chains could help lower the costs and environmental impact. Also, printing the recipe on the raw material packaging could help simplify the job of determining the mixing ratio so geopolymers can be more widely used with confidence.
Even though geopolymer technology has some drawbacks, these low-carbon alternatives have great potential for reducing emissions from the construction sector.
Alcina Johnson Sudagar, Research Scientist in Chemistry, Washington University in St. Louis
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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