Category: Chemistry

Fluorescent markers are extremely useful in science as tools to track molecules or processes as they carry out their unique activities, revealing unknown facts along the way. However, physically introducing fluorescent markers into targets can result in strong background signals, and even when chemically bound, the target’s hydrophobicity may increase, making the process far from straightforward. Moreover, fluorescent markers are often affected by the properties of the solvent in which they operate.

To address these challenges, researchers have developed a method to track the behavior of cellulose nanofibers (CNFs) by conjugating water-compatible fluorescent amino acids to the CNFs. As a result, observers can now microscopically visualize CNFs by following the blue fluorescence emitted from them.

Researchers published their results in Carbohydrate Polymer Technologies and Applications.

Cellulose nanofibers (CNFs) are a more eco-friendly alternative to conventional polymers, typically comprised of plastics, and are instead made from cellulose, a structural material found in plant cell walls. Researchers attached fluorescent amino acid acridon-2-yl-alanine, or Acd, to a CNF to produce a blue fluorescent CNF that retains the original structure and dispersibility of the materials it is acting upon and is known as Acd-CNF.

The importance of this lies in its ingenuity: conventional methods often contain hydrophobic components that can alter the thixotropic nature of some materials. Thixotropy refers to a property seen in some fluids or gels where, at rest, the material is viscous and thick but upon movement becomes more fluid (less viscous). These characteristics are essential when viewing and studying the ability of two different substances to be mixed, and can broaden the usability of CNFs.Pickering emulsion was stained with Nile Red and observed using CLSM under 405 nm excitation. Fluorescence from (A) Acd-CNF and (B) Nile Red were detected using 420–480 nm and 570–700 nm band-pass filters, respectively. (C) The panel presents a merged image of both fluorescence observations. (D) Fluorescence intensity comparison of Pickering emulsions prepared using Acd-CNF and TOCNF, evaluated based on visual observation and intensity ratio. The lower dataset represents the fluorescence intensity of Nile Red (red) and Acd-CNF (blue) for one droplet. The fluorescence intensity of Acd-CNF normalized so that its maximum value aligns with the maximum intensity of Nile Red. Credit: Carbohydrate Polymer Technologies and Applications (2025). DOI: 10.1016/j.carpta.2025.100917

“We aimed to address the challenge of visualizing the interfacial behavior and distribution of cellulose nanofibers in aqueous systems, particularly at oil-water interfaces, without relying on external dyes,” said Izuru Kawamura, senior researcher, author and professor at Yokohama National University.

The covalent bond, or bond between two atoms by sharing electrons, is a strong bond between two molecules. Acd-CNF takes advantage of this bond to increase its stability and visibility when viewing without the added “junk” that conventional dye-based methods might leave or introduce into a system. The importance of unobstructed viewing cannot be understated when attempting to understand the way substances interact with each other, as even subtle disruptions can leave the observer with biased data.

Interface science is concerned with the interactions of physical and chemical phenomena occurring at the boundary of two differing phases of matter. Acd-CNF retains the original properties of the material it acts on while being easily visible upon microscopic observation, opening up opportunities for various fields of study.

Results showed that even when the viscosity of a material was increased by 10, Acd-CNF still retained the original properties of the material. This can be attributed to its increased capacity for hydration (mitigating the hydrophobic tendencies of the conventional method) and a sturdy network of cellulose nanofibers.

Researchers would like to take this work further to explore the use of Acd-CNF in other systems, such as emulsified food products and cosmetics, and study the effects various conditions have on the product’s behaviors. Additionally, the novelty of functional fluorescent nanomaterials made out of cellulose can allow for ecofriendly nanomaterials to be put into widespread use in a variety of fields and applications.

Yuto Ito, Daisuke Sato, Azusa Kikuchi and Kawamura of the Graduate School of Engineering Science at Yokohama National University with Noriko Kanai of the Graduate School of Environment and Information Sciences at Yokohama National University contributed to this research.

A new method to convert carbon dioxide (CO2) into ethylene using significantly less energy than existing approaches could help cut emissions from one of the world’s most carbon-intensive manufacturing processes.

The catalyst at the heart of this breakthrough is the result of research led by Assistant Professor Lum Yanwei from the Department of Chemical and Biomolecular Engineering at the National University of Singapore (NUS) College of Design and Engineering.

His team developed a copper-based material enhanced with small amounts of cobalt, known as dopants, which are added just below the surface of the catalyst. These dopants alter how the copper behaves during the reaction, enabling CO2 to be converted into ethylene more efficiently and at a lower energy cost.

“By making precise changes at the atomic level, we were able to shift the most energy-demanding step in the reaction, which makes the overall process much more efficient,” said Asst. Prof. Lum. “This makes the process far more practical for industrial applications.”

The team’s research was published in the journal Nature Synthesis.

Ethylene is a key raw material used to make plastics, packaging, textiles and many other everyday products and is one of the most widely produced chemicals globally. However, most current ethylene manufacturing uses a process known as steam cracking, which involves heating fossil fuels to extremely high temperatures and releases large volumes of CO2.

If powered by affordable renewable electricity, the catalyst could could produce ethylene at a cost comparable to conventional fossil fuel-based methods. Credit: College of Design and Engineering at NUS
The new catalyst developed by Asst. Prof. Lum’s team was tested in a device known as a membrane electrode assembly, a compact, layered system that brings together the reactants, catalyst and electrical current in a tightly controlled environment. This design allows for efficient gas flow and product separation, and is commonly used in electrochemical technologies being developed for industrial use.

According to the researchers, the system delivered high ethylene output with more than 25% energy efficiency and remained stable over 140 hours of continuous operation. “We also showed that the catalyst performed well, producing ethylene from low-purity CO2, such as that found in industrial flue gas,” said Asst. Prof. Lum. “This improves its potential for real-world deployment.”

The discovery builds on earlier research led by Asst. Prof Lum, which investigated how hydrogen atoms behave during CO2 conversion. That fundamental work helped the researchers identify key bottlenecks in the reaction and informed the design of the new catalyst.

The researchers with an ultrasonic spray coating machine used to deposit the catalyst material onto the electrode. Credit: College of Design and Engineering at NUS
“Our previous work helped us pinpoint why the reaction tends to stall,” said Asst. Prof. Lum. “That gave us a clearer target for designing a better catalyst, and the results have exceeded expectations.”

A cost analysis by the research team suggests that, if powered by affordable renewable electricity, the process could produce ethylene at a cost comparable to conventional fossil fuel-based methods.

As global demand for ethylene continues to grow, the ability to manufacture it with lower carbon emissions could have a significant environmental benefit.

Threads or ropes can easily be used for braiding, knotting, and weaving. In chemistry, however, processing molecular strands in this way is an almost impossible task. This is because molecules are not only tiny, they are also constantly in motion and therefore cannot be easily touched, held or precisely shaped.

A research group at the Institute of Chemistry at Humboldt-Universität zu Berlin (HU) led by Dr. Michael Kathan has now succeeded in precisely winding two molecular strands around each other using an artificial, light-driven molecular motor, thereby creating a particularly complex structure: a catenane (from Latin “catena” = chain). Catenanes consist of two ring-shaped molecules that are intertwined like the links of a chain—without being chemically bonded to each other. The research results are published in the journal Science.

“What we have developed is basically a mini-machine that is powered by light and rotates in one direction,” says Kathan.

“We use this controlled movement to mechanically wind two molecular strands around each other and connect them—regardless of whether they would do so on their own or not. Our motor now brings a kind of mechanical control to the world of molecules, which we previously only knew from the macroscopic world.”

New method can form a large variety of specific three-dimensional structures

In synthetic chemistry, it has previously been extremely difficult to intertwine molecules in a targeted manner, especially if this arrangement contradicts the natural process of molecular self-organization. In nature, molecules are constantly in motion and can form three-dimensional structures in this process.

Structural components of cells such as proteins or the genetic molecule DNA are assembled in this way. However, these are usually not fixed and permanent structures. In the laboratory, molecular templates have often been used to define specific structures, but they typically only work with certain molecules.

The new method takes a different approach: the artificial molecular machine can force a wide variety of molecules into precisely defined three-dimensional structures. Driven by light, the rotating motor generates a mechanically defined twist with each step, which is then chemically fixed. The movement is directional and programmable.

“Our method is the first template-free approach that allows such precise mechanical control, and it is also easily generalizable,” says Kathan.

New possibilities for the design of innovative materials

The catenanes synthesized in the laboratory using the new method are considered the fundamental building blocks for mechanically intertwined structures such as molecular chains, fabrics or networks.

The study shows for the first time that such structures can in principle be produced from very different molecules and thus provides a fundamental and generalizable conceptual approach: complex, mechanically defined architectures are technically feasible at the molecular level. This broadens the scope of chemical synthesis and opens the door to designing entire materials from mechanically intertwined molecules.

These materials would possess unique properties: high flexibility combined with exceptional robustness due to their molecular architecture.

Researchers at the University of Chemistry and Technology, Prague have successfully developed a method to chemically synthesize callunene, a natural compound that protects bumblebees from a deadly gut parasite. In a recent discovery, the team also determined that the naturally occurring compound is a 50/50 mixture of its mirror-image forms, meaning the synthetic version can be used directly to safeguard vital pollinator colonies.

The study, published in the Journal of Natural Products, addresses the threat posed by the parasite Crithidia bombi. This protozoan infects bumblebees, impairing their ability to find nectar-rich flowers, which ultimately leads to starvation, reduced colony fitness, and death. The problem is especially acute in commercial indoor farming operations that rely on healthy pollinator colonies. Not only because of the farming effectiveness, but also because parasites might be spread from indoor pollinators to wild colonies.

Nature provides a defense in the form of callunene, a compound found in the nectar of heather (Calluna vulgaris). Bumblebees that forage on heather are prophylactically protected from Crithidia infection. However, the loss of heathland habitats and the difficulty of isolating the compound from natural sources have made this solution impractical on a large scale.

The UCT Prague team, led by Dr. Pavla Perlíková, overcame this challenge by developing a five-step synthesis to produce callunene in the lab. More importantly, they solved a long-standing chemical mystery about the compound’s three-dimensional structure.

“We saw a clear threat to our vital pollinators from parasites like Crithidia bombi,” said Dr. Perlíková, a lead researcher at UCT Prague. “Nature offered a solution in callunene, but it wasn’t a practical one due to its scarcity. Our goal was to make this natural protection accessible.”

Using advanced analytical techniques, including nuclear magnetic resonance (NMR) spectroscopy, the researchers analyzed both their synthetic callunene and the compound isolated from heather honey. They found that natural callunene exists as a racemic mixture—an equal blend of its “left-handed” and “right-handed” molecular forms (enantiomers).

“The most exciting part of this work was solving the stereochemical puzzle of callunene,” Dr. Perlíková explained. “Discovering that natural callunene is a racemic mixture was a game-changer. It means our synthetic version is essentially bio-identical for this purpose, and we can now produce it in the quantities needed for prophylactic studies to demonstrate its potential for use in protecting pollinator colonies. This removes a major economic and technical barrier to its use.”

This finding is significant because it means the synthetic callunene does not require an additional, often complex and expensive, step to separate the two enantiomers. The synthetic mixture can be used directly as an additive to the food of pollinators, offering a way to protect them from parasitic infections. The research opens the door for further studies and the development of new prophylactic treatments to ensure the health of these essential insects.

A research team at the Politecnico di Milano has developed an innovative single-atom catalyst capable of selectively adapting its chemical activity. This is a crucial step forward in sustainable chemistry and the design of more efficient and programmable industrial processes.

The study was published in the Journal of the American Chemical Society.

This achievement is novel in the field of single-atom catalysts. For the first time, scientists have demonstrated the possibility of designing a material that can selectively change its catalytic function depending on the chemical environment. It involves a sort of “molecular switch” that allows complex reactions to be performed more cleanly and efficiently, using less energy than conventional processes.

The research focuses on a palladium-based catalyst in atomic form encapsulated in a specially designed organic structure. This structure allows the material to “switch” between two key reactions in organic chemistry—bioreaction and carbon-carbon coupling—simply by varying the reaction conditions.

“We have created a system that can modulate catalytic reactivity in a controlled manner, paving the way for more intelligent, selective and sustainable chemical transformations,” explains Gianvito Vilé, lecturer in the Giulio Natta Department of Chemistry, Materials and Chemical Engineering at the Politecnico di Milano and coordinator of the study.

In addition to its reaction flexibility, the new catalyst stands out for its stability, recyclability and reduced environmental impact. The “green” analyses conducted by the team show a significant decrease in waste and hazardous reagents.

The study results from an international collaboration with the University of Milan-Bicocca, the University of Ostrava (Czech Republic), the University of Graz (Austria) and Kunsan National University (South Korea).

Salt creeping, a phenomenon that occurs in both natural and industrial processes, describes the collection and migration of salt crystals from evaporating solutions onto surfaces. Once they start collecting, the crystals climb, spreading away from the solution. This creeping behavior, according to researchers, can cause damage or be harnessed for good, depending on the context.

New research published June 30 in the journal Langmuir is the first to show salt creeping at a single-crystal scale and beneath a liquid’s meniscus.

“The work not only explains how salt creeping begins, but why it begins and when it does,” says Joseph Phelim Mooney, a postdoc in the MIT Device Research Laboratory and one of the authors of the new study. “We hope this level of insight helps others, whether they’re tackling water scarcity, preserving ancient murals, or designing longer-lasting infrastructure.”

The work is the first to directly visualize how salt crystals grow and interact with surfaces underneath a liquid meniscus, something that’s been theorized for decades but never actually imaged or confirmed at this level, and it offers fundamental insights that could impact a wide range of fields—from mineral extraction and desalination to anti-fouling coatings, membrane design for separation science, and even art conservation, where salt damage is a major threat to heritage materials.

In civil engineering applications, for example, the research can help explain why and when salt crystals start growing across surfaces like concrete, stone, or building materials. “These crystals can exert pressure and cause cracking or flaking, reducing the long-term durability of structures,” says Mooney. “By pinpointing the moment when salt begins to creep, engineers can better design protective coatings or drainage systems to prevent this form of degradation.”

For a field like art conservation, where salt can be devastating to murals, frescoes, and ancient artifacts, often forming beneath the surface before visible damage appears, the work can help identify the exact conditions that cause salt to start moving and spreading, allowing conservators to act earlier and more precisely to protect heritage objects.

The work began during Mooney’s Marie Curie Fellowship at MIT. “I was focused on improving desalination systems and quickly ran into [salt buildup as] a major roadblock,” he says. “[Salt] was everywhere, coating surfaces, clogging flow paths, and undermining the efficiency of our designs. I realized we didn’t fully understand how or why salt starts creeping across surfaces in the first place.”

That experience led Mooney to team up with colleagues to dig into the fundamentals of salt crystallization at the air–liquid–solid interface. “We wanted to zoom in, to really see the moment salt begins to move, so we turned to in situ X-ray microscopy,” he says. “What we found gave us a whole new way to think about surface fouling, material degradation, and controlled crystallization.”

Using in situ X-ray microscopy, researchers observed salt creep at the single crystal scale. Credit: Massachusetts Institute of Technology
The new research may, in fact, allow better control of a crystallization processes required to remove salt from water in zero-liquid discharge systems. It can also be used to explain how and when scaling happens on equipment surfaces, and may support emerging climate technologies that depend on smart control of evaporation and crystallization.

The work also supports mineral and salt extraction applications, where salt creeping can be both a bottleneck and an opportunity. In these applications, Mooney says, “by understanding the precise physics of salt formation at surfaces, operators can optimize crystal growth, improving recovery rates and reducing material losses.”

Mooney’s co-authors on the paper include fellow MIT Device Lab researchers Omer Refet Caylan, Bachir El Fil (now an associate professor at Georgia Tech), and Lenan Zhang (now an associate professor at Cornell University); Jeff Punch and Vanessa Egan of the University of Limerick; and Jintong Gao of Cornell.

The research was conducted using in situ X-ray microscopy. Mooney says the team’s big realization moment occurred when they were able to observe a single salt crystal pinning itself to the surface, which kicked off a cascading chain reaction of growth.

“People had speculated about this, but we captured it on X-ray for the first time. It felt like watching the microscopic moment where everything tips, the ignition points of a self-propagating process,” says Mooney.

“Even more surprising was what followed: The salt crystal didn’t just grow passively to fill the available space. It pierced through the liquid-air interface and reshaped the meniscus itself, setting up the perfect conditions for the next crystal. That subtle, recursive mechanism had never been visually documented before—and seeing it play out in real time completely changed how we thought about salt crystallization.”

Perovskite is a rising star in the field of materials science. The mineral is a cheaper, more efficient alternative to existing photovoltaic materials like silicon, a semiconductor used in solar cells. Now, new research has shown that applying pressure to the material can alter and fine-tune its structures—and thus properties—for a variety of applications.

Using the Canadian Light Source (CLS) at the University of Saskatchewan, a team of researchers observed in real time what happened when they “squeezed” a special type of perovskite between two diamonds. 2D hybrid perovskite is made up of alternating organic and inorganic layers. It’s the interaction between these layers, says Dr. Yang Song, professor of chemistry at Western University, that determines how the material absorbs, emits, or controls light.

The research team found that applying pressure significantly increased the material’s photoluminescence, making it brighter, which Song says hints at potential applications in LED lighting. The team also observed a continuous change in its color from green to yellow to red. “So you can tune the color.” Being able to observe changes to the material as they happen using ultrabright synchrotron light was critical to their research, said Song.

One of the biggest changes in the material came when the researchers applied a very large amount of pressure to the perovskite: it started glowing differently, signaling that its ability to handle light had improved. They also found the material squished more in one direction than others and that its internal structure became less twisted. Most similar materials become more twisted when they’re squeezed. The findings of the research, which also involved the Advanced Photon Source (APS) at Argonne National Laboratory in Chicago, were published recently in the journal Advanced Optical Materials.

Their study, says Song, demonstrates that perovskite’s “optical and electronic properties can be tuned and optimized toward application in a wide variety of devices” like LEDs and photovoltaics.

Song says the knowledge gained at the CLS about how pressure changes the structure of perovskite provides a recipe “to help the chemist or materials scientist create materials that exhibit the desirable properties.” It is, he said, information that will be key in the design of the next generation of perovskite for various uses.

Quantum sensing has transformational potential across many areas of technology and science, most prominently biomedical research. The basic premise is to detect and manipulate the spin state of an electron—magnetic properties of electrons that can be used to store quantum information using light. This capability has previously been limited to highly exotic or expensive materials such as nano-sized diamonds with specific atomic defects.

Now, in a paper published in Nature Chemistry, scientists have reported an organic molecule built from carbon atoms in which its optical properties are intrinsically linked to its electron’s spin. It’s based on two small molecular units, each carrying an unpaired electron (known as spin radical). \

When these two units are connected to form a diradical, the two electron spins can align in two different ways: pointing in the same direction (called a triplet state) or in opposite directions (a singlet state).

“The fine-tuned molecular design is key to achieving reliable interaction between the two spin radical units,” says Dr. Petri Murto, working in the group of Professor Hugo Bronstein, Yusuf Hamied Department of Chemistry, University of Cambridge.

The interaction between the two electron spin configurations controls the color of the molecule when a photon—a particle of light—is absorbed in the diradical.

“When the two electron spins are pointing in the same direction, the molecule emits orange light; but when the two electron spins are pointing in opposite directions, the molecule emits near infra-red light,” explains Rituparno Chowdhury, first author and Ph.D. student working in the group of Professor Sir Richard Friend in the Department of Physics, University of Cambridge.

“This allows you to very easily detect and know the quantum states of the molecule just by looking at the color.”

Because the quantum states of a molecule are extremely sensitive to their environment—such as magnetic fields, temperature, or chemical surroundings—scientists can detect changes in the environment with far greater sensitivity than using traditional (‘classical’) materials.

The color shift observed is connected to a known model for magnetic materials where the Hubbard energy is the cost of placing two electrons on the same site. This model is widely used for inorganic materials, including high-temperature superconductors.

“By applying a magnetic field, we can push the molecule into the triplet state and make it glow orange. At low temperatures, without the field, the singlet state dominates, and the molecule glows in the near infrared. With microwave pulses, they can also drive transitions between the states—a kind of coherent spin control normally seen in much more complex solid-state systems,” adds Dr. Alexei Chepelianskii, Université Paris-Saclay.

“The color output can be tuned using temperature or a magnetic field. I would never have believed materials like this could even exist. This opens up a whole new class of carbon-based materials with controllable spin-optical properties—materials that are not only highly luminescent but also much simpler to process than traditional materials,” notes Professor Hugo Bronstein, Yusuf Hamied Department of Chemistry, University of Cambridge.

In an earlier research, scientists at the Cavendish Laboratory had already shown that individual spin-radical units could be used to make highly efficient organic light-emitting diodes (OLEDs) operating in the red and near-infrared.

“With this new advance, we have taken a step further: showing how spin interactions in carefully designed diradical molecules can tune how the molecule responds to light, and in turn, how that light can be used to read out or even control the spin state,” remarks Professor Sir Richard Friend, Cavendish Laboratory, University of Cambridge.

This new discovery opens the door to molecular-based quantum information and sensing technology, where small size, chemical control and low cost could accelerate implementation.

A new study in Scientific Reports reveals that all Arabica coffee follows the same color development pattern during roasting, potentially transforming quality control and industry standards.

For a long time, coffee roasting has blended science with artistry, as skilled roasters depend on visual, auditory, and olfactory cues to pinpoint the ideal roast.

However, new research from the UC Davis Coffee Center has uncovered something remarkable. Despite wildly different roasting profiles, techniques, and coffee origins, all Arabica coffee follows the same universal color curve as it transforms from green bean to dark roast.

The study establishes a mathematical relationship that could finally bring objective, quantitative standards to an industry that has relied on subjective assessments for decades. The findings emerge from the most comprehensive study of commercial-scale coffee roasting color dynamics ever conducted.

Phys.org spoke to corresponding author Irwin R. Donis-González, Associate Professor of Cooperative Extension in Postharvest Engineering at the Department of Biological and Agricultural Engineering at UC Davis.

“Since I started working in postharvest, I’ve been truly fascinated by the significance of color,” said Donis-González. “Color isn’t just about appearance; it’s a key indicator of quality for many products, including coffee.”

Breaking down the roasting mystery

The researchers addressed a missing piece in our scientific understanding of coffee.

Although color has long been considered vital for assessing roast level and quality, there has been surprisingly little understanding of how roasting variables such as temperature and time in commercial roasters affect color development.

Most earlier studies relied on basic laboratory ovens set to constant temperatures, which do not reflect the complex and changing conditions found in commercial roasting. The UC Davis team took an entirely different approach.

“We established the roast profiles based on comprehensive sources, including scientific literature, prior practical experience, and established industry guidelines,” explained Donis-González.

“Using a commercial drum roaster, we systematically varied the temperature ramp rates—also known as rates of rise—to observe their effects on coffee color development throughout the entire roasting process.”

The researchers tested seven dramatically different roasting profiles, each lasting exactly 16 minutes but with vastly different energy dynamics, from “fast start” profiles with high initial heat to “slow start” approaches with gradual temperature increases.

They sampled the roasting coffee every single minute, creating an unprecedented high-resolution picture of how color develops throughout the process.Pictures showing the color of the ground coffee samples for the seven roast profiles using the washed Ugandan coffee (USF). Credit: Scientific Reports (2025). DOI: 10.1038/s41598-025-06601-w

The science behind the curve

The most striking discovery came when the team plotted their color measurements in the L*a*b* color space.

The L*a*b* color space is a scientific color system designed to match human visual perception. The L* coordinate represents lightness, while a* covers the green-to-red spectrum and b* spans blue-to-yellow hues.

“The L*a*b* color space is particularly adequate for quantifying roast color development because it can detect subtle variations that might be missed by the human eye, ensuring reliable evaluation across different lighting conditions and reducing subjective bias,” said Donis-González.

Regardless of whether they used fast, slow, or medium roasting profiles, and whether the coffee came from Uganda, Indonesia, or El Salvador, every single sample followed the same fundamental pathway in the L*a*b* color space.

The researchers could describe this “universal roasted coffee color curve” with precise mathematical equations. Their polynomial equations could predict one color coordinate from another with over 93% accuracy.

The relationship between the lightness (L*) and the red-green (a*) coordinates explained 93.4% of color variance, while the lightness and blue-yellow (b*) relationships accounted for 97.7%.

This consistency suggests that the fundamental chemical processes occurring during roasting—primarily Maillard reactions that create the brown colors and flavors associated with roasted coffee—follow predictable pathways regardless of the specific conditions used to drive them.

Even more surprisingly, despite different timing and dynamics, all coffees reached virtually identical color values at major roasting milestones such as color change, first crack, and second crack, which are the key stages roasters use to judge roast development.

“The industry was initially unaware of a key finding from our study. Despite variations in roast profile dynamics that affect roast color development, the coffees consistently display roughly the same L*a*b* color values at important roast milestones,” noted Donis-González.

Validating universality across the globe

To verify their findings weren’t limited to their specific setup, the researchers conducted a systematic review following rigorous scientific protocols.

The research team analyzed color data from 20 different publications spanning various roasting methods, equipment types, and coffee origins. That’s a total of 392 distinct measurements.

The validation was remarkable. Most existing data aligned perfectly with their universal curve, with 86% of data points showing no perceptible color differences from the predicted values.

“A systematic review was essential in confirming the existence of a universal color curve for Arabica coffee,” said Donis-González. “We were especially surprised by the consistency, which underscores the shared characteristics in coffee color development regardless of origin or processing method.”

The universality even extended beyond coffee. Data from bread baking, another process involving Maillard browning reactions, also followed similar color relationships, suggesting the curve might apply to other food processing applications.

Looking to the future

Currently, there are no universally accepted standards for terms like “light roast,” “medium roast,” or “dark roast.” One roaster’s light roast might be darker than another’s “dark roast,” creating confusion for consumers and inconsistencies throughout the supply chain.

“This universal coffee color curve can help standardize roast-level definitions industry-wide by providing an objective, measurable way to assess roast levels through color analysis,” explained Donis-González.

The practical applications extend far beyond standardization. Roasters could use the universal curve for real-time quality control, knowing exactly where their coffee sits on the universal color pathway regardless of their specific roasting profile.

The research team is now working to connect their L*a*b* measurements with existing roast level scales, such as Agtron and Colorette, ensuring the universal curve can be used with current industry equipment.

“We can now present the universal roasted coffee color to industry professionals, who, through systematic surveys, can assist in categorizing and naming the colors of roasted coffee based on their experience and industry standards,” said Donis-González.

Penn materials scientist Shoji Hall and colleagues have found that manipulating the surface of water can allow scientists to sustainably convert carbon monoxide to higher energy fuel sources like ethylene.

As human-made pollutants carbon monoxide (CO) and carbon dioxide (CO₂) continue to accumulate in Earth’s atmosphere, fueling climate change and threatening ecological balance, researchers are searching for new ways to recycle these chemicals into cleaner power sources and products.

Multi-carbon products like ethylene (C₂H₄) hold promise to turn carbon’s doom into a boon. It’s a molecule held together by strong bonds formed by its carbon atoms sharing electrons. When these bonds are broken, like in combustion, they can release that stored energy as heat, making these compounds a useful fuel source. If they stay intact, they can serve as building blocks for countless manufactured goods, from packaging to textiles and pharmaceuticals.

But the chemistry behind turning CO and CO₂ into multi-carbon products like C₂H₄ is notoriously tricky. So much so, even popular metals like copper catalysts can often produce unwanted byproducts or waste energy in side reactions.

Now, researchers led by University of Pennsylvania materials scientist and engineer Anthony Shoji Hall have uncovered an unlikely ally in the fight to make good carbon-based products from carbon waste: the surface of water.

Their findings, published in Nature Chemistry, reveal that by precisely tuning the concentration of a salt called sodium perchlorate (NaClO₄) dissolved in water, the researchers could disrupt the neat, normally ordered hydrogen bonding network of water molecules right where the liquid meets metals like copper. This is a process known as electrochemical catalyzation—using electricity, water, and metal surfaces to drive the conversion of CO to multi-carbons like C₂H₄.

“This ‘jumble’ of water molecules at the interface—where liquid meets solid metal—turned out to be the missing spark for stitching carbon atoms together, a step that has long throttled our ability to convert CO into ethylene and other multi-carbons,” says Hall, an associate professor in the Department of Materials Science and Engineering in the School of Engineering and Applied Science.

This hydrogen-bonded structure can be likened to a microscopic spiderweb, that when disrupted, becomes disordered, and that, it turns out, makes it easier for carbon atoms to join up and form larger products like ethylene.

“What excites me most is the simplicity,” he says. “If something as familiar as liquid water can be subtly adjusted to promote these reactions, we can start recycling problem gases like CO and CO₂ into valuable fuels or industrial chemicals without relying on exotic or expensive solvents.”

To test their hypothesis, the Hall Lab ran electrochemical reactions on copper-coated electrodes, which are metal surfaces that carry electrical current into the experimental environment. They submerged these into the salty water solution containing CO.

Gradually, they increased the amount of NaClO₄ in the water, allowing them to measure how efficiently CO was converted into various products such as ethylene, as well as the rate at which the reactions occurred as the water-based salty solution—or electrolyte—became more concentrated in NaClO₄.

Meanwhile, co-corresponding author David Raciti of the National Institute of Standards and Technology (NIST) used a specialized form of light-based chemical sample analysis to zoom in on the water layer right at the metal surface, enabling real-time monitoring as the NaClO₄ levels rose.

As the NaClO₄ concentration increased from 0.01 to 10 molal, the system’s Faradaic efficiency—a measure of how many negatively charged particles (electrons) go toward making the desired products—jumped from 19% to 91%. Hydrogen gas, an unwanted byproduct, nearly disappeared. And ethylene emerged as the clear front-runner, with its production increasing eighteenfold.

To see if positively charged hydrogen atoms, or protons, were playing a role in driving the reaction speed instead of the entropy results they expected, the researchers swapped regular water for heavy water (deuterium oxide, or D₂O), which slows down proton transfer during electrochemical reactions.

Typically, in such electrochemical reactions, protons “shuttle” from water to surface-bound molecules, helping complete bonds and form products. But the researchers found the reaction was barely changed by proton movement but rather by entropy, or the growing disorder among water molecules at the interface that, somehow, made it easier for carbon atoms to link up.

“In most electrocatalysis studies, we focus on activation energy—the idea that lowering the energy barrier makes a reaction go faster,” says Hall. “But here, it’s entropy driving the reaction. That’s unusual, and it opens a new way of thinking about how to control surface chemistry.”

Beyond being a technical accomplishment, the implications are wide-ranging, as water is a universal component in electrochemical systems ranging from CO₂ conversion to battery design. Their work suggests that engineers may be able to fine-tune water’s interfacial structure—where water meets a surface—to coax better performance from a wide range of reactions.

“Electrochemistry is full of hidden levers,” Hall says. “And we think interfacial water structure is one of the biggest ones. With the right tools, we can stop treating water as just a solvent and start using it as a co-designer of the reaction environment.”

Looking ahead, Hall’s lab hopes to apply this strategy to more complex reactions, such as coupling carbon sources with nitrogen to produce fertilizer precursors. More broadly, the Hall Lab is exploring how interfaces can be engineered to guide chemical transformations with surgical precision.