CHEyhun

Better together

Shown here are two nanoparticles with cadmium cores encased in cadmium chloride shells, growing and merging with each other over the course of about 50 seconds. The union of the particles was recorded by Qiubo Zhang, a postdoc in Haimei Zheng’s lab at Lawrence Berkeley National Laboratory, using high-resolution liquid cell transmission electron microscopy (LC-TEM). The video shows that the particles’ growth is guided by a defect in the right-hand particle’s shell, which contradicts long-held notions about how particles in solution combine through a size-driven process known as Oswald ripening.

Zheng’s group uses advanced TEM methods to look how nanoscale imperfections impact dynamic physical and chemical processes. Understanding the factors that influence nanoparticles’ growth, Zheng says, will help scientists design better materials for use in catalysis and energy storage. The team published their findings in Nature Communications earlier this year (DOI: 10.1038/s41467-022-29847-8).—Brianna Barbu  

Credit: Haimei Zheng/LBNL

Do science. Take pictures. Win money. Enter our photo contest here.

Three microscopes see more than two

One has to look very closely to understand what processes take place on the surfaces of catalysts. Solid catalysts are often finely structured materials made of tiny crystals. There are various microscopies to monitor chemical processes on such surfaces—they use, for example, ultraviolet light, X-rays or electrons. But no single method alone provides a complete picture.

This is why research teams from TU Wien and the Fritz Haber Institute in Berlin have developed a novel approach that allows to have “triple eyes” on a catalytic reaction—using three different surface microscopies. This way, they were able to show that during the catalytic conversion of hydrogen and oxygen to water, reaction fronts on the crystal surface not only form remarkable geometric patterns, but also a new mechanism of the propagation of these fronts was discovered.

For climate-relevant technologies such as ecologically clean hydrogen-based energy production, a comprehensive understanding of such processes is crucial.

Creating hydrogen storage materials from industrial waste

Whether it is cars, energy or mobile phones, modern society is built on metals, and our future strongly depends on these materials, too. To store hydrogen in a safe, compact and still environmentally friendly way is still a major challenge. Metal hydrides could be an appealing solution, especially for those applications where the volume and safety of the storage system is an issue—for example, in stationary storages, in hydrogen refueling stations or ships—as they can provide a very high storage density. High-purity metals are commonly used to produce these storage materials. Despite their advantages, the mining and large-scale production of these materials is a heavy burden on the environment as they emit large amounts of greenhouse gases, not to speak of the impact of mining of the raw materials on the landscape itself.

Researchers at the Helmholtz-Zentrum Hereon Institute of Hydrogen Technology have now shown that high-quality hydrogen storage materials can also be produced from less pure industrial metal wastes. These findings allow us for the first time to use a circular economy strategy to produce metal hydrides. As a result, their production is much more environmentally friendly.

“The utilization of circular economy approaches to the production of hydrogen storage materials allows us to tackle the energy challenges that modern times pose to our society in a more sustainable manner,” says Dr. Claudio Pistidda, scientist at the Hereon Institute of Hydrogen Technology.