Rewritten Article:

Scientists have made a groundbreaking discovery that could revolutionize the production of green hydrogen, a crucial component for a sustainable energy future. Researchers have found that a cage-structured material, previously unknown as an electrocatalyst, can outperform existing nickel-based catalysts in electrolytic hydrogen production. This breakthrough has significant implications for the chemical industry and our transition to renewable energy sources.

The study, published in Angewandte Chemie, investigates the suitability of clathrates – materials characterized by a complex three-dimensional cage structure – as catalysts for oxygen evolution reaction (OER) in electrolysis. Clathrates have shown promise in various applications, such as thermoelectrics and superconductors, but their potential as electrocatalysts has remained unexplored until now.

Dr. Prashanth Menezes and his team at the Technical University of Munich synthesized Ba₈Ni₆Ge₄₀ clathrates, which they then tested as OER catalysts in aqueous electrolytes. The results were astonishing: the clathrate sample exceeded the efficiency of nickel-based catalysts at a current density of 550 mA cm⁻², a value commonly used in industrial electrolysis. Moreover, its stability was remarkable, with activity remaining high even after 10 days of continuous operation.

To understand why this material performed so well, the researchers employed a combination of experiments, including in situ X-ray absorption spectroscopy (XAS) at BESSY II and basic structural characterization at the Freie and Technische Universität Berlin. Their analysis revealed that the clathrate particles undergo a structural transformation under an electric field: germanium and barium atoms dissolve out of the former three-dimensional framework, leaving behind highly porous, sponge-like nanolayers of nickel that offer maximum surface area.

“This transformation brings more and more catalytically active nickel centres into contact with the electrolyte,” says Dr. Niklas Hausmann from Menezes’ team. “We were actually surprised by how well these samples work as OER catalysts. We expect that we can observe similar results with other transition metal clathrates and that we have discovered a very interesting class of materials for electrocatalysts.”

This breakthrough has significant implications for the production of green hydrogen, which is seen as an essential building block for a sustainable energy future. With this new material, researchers may be able to develop more efficient and robust OER catalysts, enabling faster and more cost-effective production of green hydrogen.

The world is shifting towards renewable energy sources, and hydrogen-based technologies are gaining attention. However, a new study suggests that the conventional thinking on single atom catalysts (SACs) might be limiting their potential. Researchers have found that the metal site in SACs can be improved by pushing the limits of design, optimizing the hydrogen evolution reaction (HER), and addressing the poisoning effects of HO* and O*. This breakthrough could lead to more efficient energy storage or hydrogen production.

Single atom catalysts are catalytically active metal sites distributed at the atomic level to enhance catalytic activity. However, hydroxyl radical (HO*) and oxygen radical (O*) poisoning can alter molecules and degrade performance. In contrast, sites where hydrogen molecules don’t readily accumulate can lead to an enhancing effect of the catalyst.

Researchers have discovered that HO* poisoning, realistic H* adsorption strengths at active metal sites, and the potential HER activity at coordinating N-sites are crucial factors to consider for accurate descriptor development. By effectively modifying these factors, more efficient catalysts can be developed to improve HER activity while not relying on conventional design of metal binding sites.

The study found that hydrogen binding energy (HBE) calculation under a realistic representation of accumulated molecules (adsorption) can serve as a good predictor of HER activity. Additionally, the combination of using HBE and Gibbs free energy as descriptors for SACs provides new guidelines for those working with this catalyst design.

This work addresses the long-lasting debate on HER descriptors and provides new methods to break out of conventional limitations put on by using just hydrogen binding energy as a solo descriptor. The researchers aim to further address the limitations of HO poisoning and develop novel single- and dual-atom catalysts for different pH conditions, especially in alkaline environments.

In conclusion, this study opens up new possibilities for SACs, highlighting the importance of pushing design limits, optimizing HER, and addressing poisoning effects. By doing so, researchers can unlock the full potential of SACs and contribute to more efficient energy storage or hydrogen production.

Thermoelectric materials have long been touted as a promising solution for converting waste heat into electrical energy. However, their efficiency has always been hindered by the need to suppress lattice vibrations, which facilitate heat transfer, while also increasing electron mobility. A team of researchers led by Fabian Garmroudi has now achieved a breakthrough in this field by developing hybrid materials that decouple heat and charge transport, boosting efficiency by over 100%.

The key to their success lies in combining two materials with fundamentally different mechanical properties but similar electronic characteristics. By mixing powders of an alloy of iron, vanadium, tantalum, and aluminum (Fe2V0.95Ta0.1Al0.95) with bismuth and antimony (Bi0.9Sb0.1), the researchers created a compact material that exhibits exceptional thermoelectric properties.

The lattice structures of the two materials are so different that thermal vibrations cannot be transferred from one crystal to the other, strongly inhibiting heat transfer at their interfaces. Meanwhile, the movement of charge carriers remains unhindered due to the similar electronic structure and is even significantly accelerated along these interfaces.

The BiSb material forms a topological insulator phase, enabling almost loss-free charge transport on its surface. This targeted decoupling of heat and charge transport has allowed the team to increase the efficiency of the material by more than 100%, bringing them closer to their goal of developing a thermoelectric material that can compete with commercially available compounds based on bismuth telluride.

The new hybrid materials offer several advantages over traditional thermoelectrics, including increased stability and lower production costs. As researchers continue to refine this technology, it has the potential to revolutionize energy harvesting and conversion in various applications, from small-scale devices to industrial processes.