Scientists create a hexagonal diamond that could be even harder than the real thing

To misquote a famous song, "Diamonds are industry's best friend." Cubic diamond is the hardest mineral on Earth and is used in everything from precision cutting tools to high-performance semiconductors as well as expensive jewelry. But there is a rare and potentially tougher form called hexagonal diamond (HD), which has long been the subject of theories and debate over its actual existence. But now researchers from China claim to have created this elusive form of carbon in the lab. Hexagonal diamond (also known as lonsdaleite) is usually found at sites of meteorite impacts. But because the quantities are so small and mixed with minerals, some scientists doubted it was a distinct material. In a paper published in the journal Nature, researchers describe how they made a bulk piece of pure HD using extreme pressure and heat.

Newly synthesized fullerene material remains metallic even under low temperatures

An international team whose research was coordinated by Osaka Metropolitan University (OMU) has reported the survival of metallic behavior in the strongly correlated molecular material ytterbium cesium fulleride (Yb₂CsC₆₀). The electrons in the newly synthesized material remained mobile and continued to conduct electricity even at the lowest temperatures studied, despite strong electron interactions that would normally be expected to drive the material into an insulating state. The findings were published in Nature Communications. In materials such as metals, electrons move freely, allowing them to conduct electricity. However, as interactions between electrons become stronger, freedom of motion can be suppressed. Under these conditions, materials undergo a phenomenon known as a Mott metal-insulator transition, where they change from a conducting metal into an insulating state in which electrons become effectively immobile.

Prussian Blue finally transformed into octahedral structure after 300 years

For the first time in more than three centuries, Prussian Blue—long confined to its rigid cubic shape—has been transformed into an octahedral structure. A research team has successfully synthesized this new morphology by replacing water with a specialized solvent, glycerol, during the crystal growth process. Their findings were recently published online in Advanced Functional Materials. Accidentally discovered around the 1700s, Prussian Blue possesses a hollow three-dimensional framework that allows ions to move in and out with ease. These unique properties have enabled its use across diverse fields, from sodium-ion battery electrodes to radioactive cesium removal, catalysis, and environmental remediation. However, until now, its morphology had been limited. When synthesized in water, the reaction proceeds too quickly, making it difficult to control particle growth and producing only cubic particles. This constraint has prevented scientists from exploring shape-dependent properties or unlocking new applications.

Sustainable chemistry: Iron substitutes noble metals in catalytic reactions

The production of many products used in everyday life and in industry, such as pharmaceuticals, plastics, and coatings, requires chemical catalysts, often expensive noble metals with limited availability. Researchers at the Karlsruhe Institute of Technology (KIT) are now presenting the first air-stable iron compound, which enables the direct use of iron(I) for catalysis and, unlike previous methods, does not require strong reducing agents. A first test yielded active iron catalysts. The study, "A Simple, Air Stable Single-Ion Source of Iron(I)," is published in the Journal of the American Chemical Society. Catalysts are required to speed up chemical reactions or even make them possible at all. The catalysts generally used in industry are noble metals, such as rhodium, iridium, or palladium. They are highly effective for many applications, but at the same time expensive and rare.

Cracking a long-standing problem in high-entropy alloy nanoparticle synthesis

Composed of five or more elements in nearly equal amounts, high-entropy alloys (HEAs) have emerged as promising catalysts due to their compositionally complex surfaces that can accelerate chemical reactions. Until now, scientists have not been able to precisely engineer these surface structures at the nanoscale, making it difficult to study how particle shape influences catalytic performance. Now, a study led by Northwestern University professors Chad A. Mirkin and Christopher M. Wolverton has solved that problem. The research is published in the Journal of the American Chemical Society.

Backyard leafhoppers inspire next-generation cloaking tech

Engineers are borrowing the insects' trick, an ‘invisibility cloak’ of anti-reflective spheres

From Harry Potter to The Lord of The Rings, tall tales regale us with the potential benefits of invisibility. Many researchers would like to bring such benefits to the real world. One new tech might allow some things to practically hide in plain sight. Its inspiration: the common backyard leafhopper. A camouflage artist, this insect is an expert nanoengineer. An adult leafhopper coats its body with a liquid. That goo is filled with tiny, complex nanospheres. These anti-reflective, soccer-ball-shaped objects are called brochosomes (BROK-ih-zoams). As light hits them, they change its behavior, explains Roman Rakitov. He works at the Russian Academy of Sciences in Moscow. An insect biologist, he did not work on the new study.

Why promising CO₂-to-fuel catalysts keep falling short of copper

Technology that converts carbon dioxide (CO₂) into fuels and plastic feedstocks using electricity is gaining attention as a core technology in the era of carbon neutrality. In particular, ethylene and ethanol are high-value materials widely used in the production of plastics, fuels, and chemical products, but until now, the only metal that has effectively produced them has essentially been copper (Cu). Through this study, Korean researchers have revealed the limitations of existing catalyst theories that have explained this principle. A research team led by Professor Jihun Oh from KAIST's Department of Materials Science and Engineering, through joint research with Professor Stefan Ringe's team from the Department of Chemistry at Korea University, has identified a new operating principle of the electrochemical CO₂ reduction reaction (CO₂ reduction reaction, a reaction that uses electricity to convert carbon dioxide into other chemical substances). The study is published in the journal Nature Catalysis.

Room-temperature multiferroic could pave way to low-energy computing

A team of researchers at Rice University has engineered a new version of a well-known multiferroic that exhibits orders of magnitude higher performance at room temperature than its parent material. The study, published in the Proceedings of the National Academy of Sciences, describes a modified version of bismuth ferrite that shows a 10-fold increase in magnetization and 100-fold increase in magnetoelectric coupling compared to standard varieties. The synthesis process entailed mixing bismuth ferrite with barium titanate while simultaneously growing the material as a thin film on a substrate that distorts its crystal structure.