Using individual atoms to achieve fossil-free chemistry

ETH Zurich

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Each of the isolated indium atoms (in gold color) can catalyse the synthesis of methanol (top right)

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Credit: (Graphic: Constance Ko / ETH Zurich)

Every chemical reaction faces a barrier: for substances to react with one another, it is first necessary to supply energy. In many cases, this energy barrier is low – such as when striking a match. For many key reactions in industry, however, it is much larger – and increased energy requirements drive up production costs. To lower this barrier, chemists use “reaction helpers” known as catalysts. The best of these substances contain metals – including, in some cases, rare metals. 

Better, more efficient and leaving nothing to chance 

Now, chemists from ETH Zurich have achieved a breakthrough in catalysis research on multiple levels: 

• They have developed a catalyst that significantly lowers the energy barrier for the production of methanol – an alcohol – from the greenhouse gas CO2 and hydrogen. 
• In their catalyst, the researchers use the metal indium in an extremely efficient manner – in the sense that each individual indium atom behaves as an active site. 
• In the past, catalysis research often followed a “hit or miss” approach. The newly discovered catalyst allows more precise analysis of the mechanisms taking place on its surface, paving the way for rational catalyst design. 

The Swiss army knife of green chemistry 

“Methanol is a universal precursor for the production of a wide range of chemicals and materials, such as plastics – the Swiss army knife of chemistry, so to speak,” says Javier Pérez-Ramírez, Professor of Catalysis Engineering at ETH Zurich. The liquid therefore plays a vital role in the transition to sustainable and fossil-free production of chemical products and fuels. 

If the energy used to produce the hydrogen and for catalysis is generated sustainably, methanol can ultimately even be produced in a climate-neutral manner. This provides a way of using CO2 from the atmosphere as a raw material instead of merely releasing it as we do today. 

Maximum use of the metals 

“Our new catalyst has a single atom architecture, in which isolated active metal atoms are anchored on the surface of a specially developed support material,” Pérez-Ramírez explains. In conventional catalysts, on the other hand, metals are usually present as aggregates, usually small particles. Although these particles are tiny, they often contain between a hundred and several thousand metal atoms.  

It is no wonder that single-atom catalysts are currently a hot topic in catalysis research. They represent the pinnacle of efficiency when it comes to the use of expensive and scarce chemical elements. If metals are used as individual atoms, it can even be possible to use precious metals in an economically viable manner. 

If the atoms can work in isolation, their catalytic properties also frequently change. “Indium has already been used in this catalyst for over a decade,” says Pérez-Ramírez. “In our study, we show that isolated indium atoms on hafnium oxide allow more efficient CO2-based methanol synthesis than indium in the form of nanoparticles containing large numbers of atoms.”  

Single atoms in the right place 

In order to anchor single indium atoms to the hafnium oxide surface in a targeted manner, the interdisciplinary ETH team developed various synthetic pathways in collaboration with colleagues from other research institutions. One key part of this development was the specific structure of the support material, which provides the atoms with a stable and, at the same time, reactive environment. 

In one tested production process, the starting materials are combusted in a flame at 2,000 to 3,000°C and then rapidly cooled. Under these conditions, the indium tends to remain on the surface, where it is stably incorporated.  

With the incorporation of the catalyst atoms into a heat-resistant hafnium oxide support, the ETH chemists show that single-atom catalysts can remain stable even in extreme conditions. Reactions that require high temperatures and pressures are therefore also within reach. For example, the synthesis of methanol from CO2 and hydrogen gas requires temperatures of up to 300°C and pressures of up to 50 times normal atmospheric pressure. 

Interaction between catalyst metal and matrix 

Moreover, the existing nanoparticles used for analysis were a black box. While the catalytic processes only took place at the small number of atoms on the surface, many measurement signals originated from inside the particles, from atoms that were not even involved in the reaction. This made interpretation more difficult. In catalysts with isolated atoms, however, the reaction mechanisms can be analysed with far fewer interfering signals. 

Pérez-Ramírez has not only been researching better catalysts for methanol production from CO2 at ETH since 2010 but also works closely with industry and holds several patents in this area. One key factor in the development of the new single-atom catalyst method was the large network that has emerged in terms of catalysis research in Switzerland in recent years, says Pérez-Ramírez: “The development of the methanol catalyst and the detailed analysis of the mechanism would not have been possible without this interdisciplinary expertise.”  

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Journal

Nature Nanotechnology

DOI

10.1038/s41565-026-02135-y 

Article Title

Single atoms of indium on hafnia enable superior CO2-based methanol synthesis

Article Publication Date

2-Mar-2026

 

Black soldier fly larvae show promise for safe organic waste removal

American Chemical Society

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People and animals create lots of waste that is usually sent to landfills, incinerated or stored in engineered ponds such as manure lagoons. Now, researchers publishing in ACS’ Environmental Science & Technology Letters report a potential removal method using insects, specifically black soldier fly larvae. In experiments, the larvae ate spoiled food, sewage sludge or livestock manure, and removed most human-pathogenic viruses. The researchers say this demonstrates a step toward simple, environmentally friendly waste management.

"Viruses in organic wastes have rarely been studied in a systematic way, but our research shows that black soldier fly larvae can help reduce potential viral risks, highlighting the promise of this approach for future waste treatment,” says Gang Luo, a corresponding author of the study.

Zhijian Shi, Luo and colleagues wanted to see how well black soldier fly larvae break down RNA viruses in three organic waste streams, or if viral material persists in their bodies or appears in their frass (tiny, nutrient-rich pellets larvae excrete). The researchers fed separate groups of black soldier fly larvae food waste, sewage sludge or pig manure. After eight days, all the larvae gained weight, with those that ate food waste growing the most, followed by those fed manure and those fed sewage. When the team members assessed the three waste streams, they found that the initial feedstocks contained a diverse array of RNA viruses that could infect living things such as bacteria, fungi, plants and animals, even humans.

Larvae that consumed food waste contained low amounts of insect-specific viruses, which the researchers consider to be of minimal ecological or human infection risk. In contrast, larvae that were fed sewage sludge or pig manure had higher viral diversity, and their frass contained RNA viruses that could infect humans. Although larval digestion significantly decreased the abundance of most human-pathogenic viruses (e.g., noroviruses) from the fecal organic matter sources to frass, some viruses (e.g., picobirnaviruses that can cause digestive symptoms) persisted in both the final larvae and frass.

The researchers conclude that black soldier fly larvae are a promising simple and natural approach for waste management, but larvae consuming fecal wastes may need additional treatment for safe use in feed or for their frass to be used in fertilizers. Future research will focus on whether viruses remaining in larvae or their frass are still active. Gang Luo says this is “key to safely reusing them in a circular waste management system.”

The authors acknowledge funding from the National Natural Science Foundation of China.

The paper’s abstract will be available on March 4 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.estlett.5c01207   

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The American Chemical Society (ACS) is a nonprofit organization founded in 1876 and chartered by the U.S. Congress. ACS is committed to improving all lives through the transforming power of chemistry. Its mission is to advance scientific knowledge, empower a global community and champion scientific integrity, and its vision is a world built on science. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, e-books and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

Registered journalists can subscribe to the ACS journalist news portal on EurekAlert! to access embargoed and public science press releases. For media inquiries, contact newsroom@acs.org.

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Journal

Environmental Science & Technology Letters

DOI

10.1021/acs.estlett.5c01207 

Article Title

Unveiling the Hidden RNA Virus Diversity in Organic Wastes: Shaping and Reduction Effects of Black Soldier Fly Treatment

Article Publication Date

4-Mar-2026

 

Photocatalytic material class: High expectations reinforced

First systematic computational investigation of polyheptazine imides published

Helmholtz-Zentrum Dresden-Rossendorf

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Three layers of a silver ion-doped polyheptazine imide polymeric network. In this example the metal ions are located between the layers, inducing lattice expansion and structural distortion. However, the polymeric backbone remains intact. Only the pore geometry changes.

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Credit: B. Schröder/HZDR

Photocatalysis promises an efficient conversion of abundant solar energy into usable chemical energy. Polyheptazine imides have some key structural and functional twists that make them especially interesting for photocatalysis. So far, there was only limited knowledge about how structural changes affect the electronic and optical properties of the many material candidates in this class. A team led by researchers from the Center for Advanced Systems Understanding (CASUS) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has now presented a reliable and reproducible theoretical method to solve this challenge that was confirmed by measurements done on genuine candidate materials (DOI: https://doi.org/10.1021/jacs.5c09930). The scientists expect the field of polyheptazine imide materials research to undergo a boom.

Polyheptazine imides belong to the family of carbon nitrides, which are layered, graphene-like compounds composed of nitrogen-rich, ring-shaped units. Unlike graphene, which exhibits excellent electrical conductivity but lacks photocatalytic activity, polyheptazine imides possess band gaps suitable for visible-light absorption.

Carbon nitride-based materials impress due to their low production cost, nontoxicity and thermal stability. However, the first generation of such materials were not ideal photocatalysts as the materials possessed properties that hindered charge separation. If a material has a low charge separation, the electron excited by an incoming photon quickly recombines with the hole it was propelled from – and releases energy only as heat or light. No energy is available to drive chemical reactions. “Polyheptazine imides containing positively charged metal ions exhibit markedly improved charge separation. This feature renders them highly suitable for practical applications,” says first author Dr. Zahra Hajiahmadi.

Computer science narrows down options

Better materials are for instance needed to realize the expected economic potential of photocatalytic reactions like water splitting (to produce hydrogen as a fuel), carbon dioxide reduction (to produce basic carbohydrates as fuels or industrial chemicals) or hydrogen peroxide production (as a basic industrial chemical). To successfully design a polyheptazine imide material that catalyzes a desired reaction smoothly, researchers have to fine-tune every aspect of the material. Obviously, this cannot be done by synthesizing every possible candidate material. This is where computer science comes to the rescue.

“The design space is enormous,” says Prof. Thomas D. Kühne, Director of CASUS, leader of the CASUS research team “Theory of Complex Systems” and senior author of the new publication. “One can for example add functional groups on the surface or substitute specific nitrogen or carbon atoms with oxygen or phosphorus atoms.” Kühne’s group at CASUS is developing novel numerical techniques, which are as efficient as possible and yet, at the same time, qualitatively reproduce the correct chemistry and physics of the underlying system.

Finding the perfect material – in a systematic way

Hajiahmadi’s research focused on the key feature of polyheptazine imides: the negatively charged pores that can be equipped with positively charged metal ions. This setup can greatly enhance catalytic activity. Hajiahmadi’s work is the first comprehensive study on the influence of different metal ions on the optoelectronic properties of polyheptazine imides. In total, 53 different metal ions were analyzed and classified with respect to their location (in plane or between the layers) and their effect on the geometry of the material (resulting in a distortion or not).

“We used a reliable and reproducible computational framework that goes beyond conventional modeling approaches,” says Hajiahmadi. “Standard computational studies of photocatalysts typically focus on ground-state properties and neglect excited-state effects, despite the fact that photocatalysis is inherently driven by photoexcited charge carriers. Specifically, we employ many-body perturbation theory methods.” Starting from an easily solvable non-interacting system, these methods treat interactions as small perturbations. The effects of interactions are calculated as small corrections to the known solution. In the end, all mathematical expansions result in an approximation of how large groups of particles influence each other. Because of their high computational cost these methods are rarely used in this field. But the presented study clearly confirms that the benefits are overwhelming as the new computational framework enables a qualitatively accurate description of a material’s optical absorption and electronic structure under illumination.

Using this approach, the scientists systematically investigated how the different metal ions influence the geometry of the polyheptazine imide polymeric network. The results show that ion incorporation can induce distinct structural distortions, including changes in layer spacing and local bonding environments. These geometric modifications directly affect the electronic band structure and optical behavior, including light-harvesting efficiency.

To validate the theoretical predictions, eight polyheptazine imides, each equipped with a different metal, were synthesized and tested for their suitability to catalyze hydrogen peroxide production. “The results clearly showed a high degree of agreement to our predictions and outperformed competing calculation methods,” Hajiahmadi concludes. Kühne adds: “If there was some doubt about polyheptazine imides being one of the most promising platforms for next-generation photocatalytic technologies, I believe this work put them to rest. The path toward the targeted design of efficient polyheptazine imide photocatalysts for sustainable reactions is clearer now. I firmly believe that it will be taken often and successfully.”

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Journal

JACS

DOI

10.1021/jacs.5c09930 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Theory-Guided Discovery of Ion-Exchanged Poly(heptazine imide) Photocatalysts Using First-Principles Many-Body Perturbation Theory

Contraception without hormones: Goethe University researches alternatives to “the pill”

German Federal Ministry of Research funds PREVENT project in Frankfurt, Bonn and Munich with €3 million

Goethe University Frankfurt

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... is the is the research goal of the German PREVENT project by Goethe University Frankfurt, University Hospital Bonn (UKB), and LMU Munich

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Credit: Markus Bernards/AI for Goethe University Frankfurt

FRANKFURT. In the 1970s, the contraceptive pill was the most frequently used method of contraception in Western countries; in Germany, for example, one in three women used “the pill.” It is safe and reliable, covered by (most) health insurances, and – particularly in the 1960s and 1970s – was also regarded as an instrument of female self-determination.

Over time, however, a number of side effects associated with hormonal contraceptive methods became apparent, from nausea, weight gain, and breast tenderness to more serious risks such as high blood pressure, liver dysfunction, and thrombosis. Some medications, such as certain antibiotics or St. John’s wort products, can reduce the effectiveness of the pill.

The pill is increasingly rejected

Although side effects occur comparatively rarely, concerns about the risks have contributed to a declining acceptance of the pill. According to recent surveys by the German Federal Centre for Health Education, since 2023 fewer women and couples have been using the pill for contraception; among younger adults in particular, the condom has replaced the pill as the number one contraceptive method.

A research team led by Dr. Claudia Tredup and Prof. Stefan Knapp from the Institute of Pharmaceutical Chemistry at Goethe University Frankfurt, Prof. Daniel Merk from Ludwig Maximilian University of Munich, and Prof. Hubert Schorle from UKB, who is also a member of the Transdisciplinary Research Area (TRA) “Life & Health” at the University of Bonn, and Prof. Jean-Pierre Allam, Head of Andrology at UKB, is now working to develop contraceptives with particularly few side effects that do not rely on hormonal mechanisms. To this end, they have launched the PREVENT project (“Precision Reproductive and Contraceptive Target Discovery Network”) and secured three years of project funding from the German Federal Ministry of Research, Technology and Space.

Active substances for new contraceptive strategies

PREVENT project leader Dr. Claudia Tredup from the Institute of Pharmaceutical Chemistry at Goethe University Frankfurt explains: “Hormonal contraceptive methods such as the contraceptive pill interfere with the body’s natural hormone cycle. In PREVENT, we are investigating for alternative non-hormonal approaches for both women and men in order to offer couples additional contraceptive options.”

The PREVENT team’s research approach focuses on so-called small molecules that specifically block proteins found exclusively in sperm or egg cells. For example, small molecules could specifically target sperm, preventing sperm from reaching the egg cell. Tredup explains: “Since contraceptives are administered to healthy individuals, they must not only be reliable and reversible, but also safe and highly tolerable.”

Given these complex requirements, the search for suitable active substances is highly demanding. The PREVENT team will therefore develop a drug discovery platform to establish technologies and tools for validating non-hormonal contraceptive concepts. Highly selective and effective compounds – so-called “chemical probes” – will enable the targeted testing of new contraceptive strategies and provide a solid foundation for preclinical and later clinical development.

Biochemist Tredup adds: “We already know of a number of genes associated with infertility. Within the PREVENT team, we want to build the expertise needed to use the corresponding proteins as target structures for safe, non-hormonal contraceptive strategies.” She is convinced that this is not just a classic pharmaceutical research project: “With PREVENT, we are also addressing key societal goals of reproductive self-determination and global health policy.”