Tag: electrodeposition

Caught in the frame: the birth of nanostructures

Caught in the frame: the birth of nanostructures

A team led by prof. Magdalena Parlińska-Wojtan from the Institute of Nuclear Physics of the Polish Academy of Sciences conducted advanced research on the process of electrodeposition of metallic nanostructures, using unique microscopic techniques in a liquid environment. International cooperation, including the Silesian University of Technology, the University of Warsaw, the SOLARIS Center, ETH Zurich, and the Fritz Haber Institute in Berlin, resulted in a publication in the prestigious journal Nano Letters.

Modern microscopes and a special electrochemical flow cell allowed scientists from the IFJ PAN to observe the process of creating metal nanoparticles with unprecedented precision. This is a step towards better design of future materials – from fuel cells to advanced sensors. 

Electrodeposition is the process of depositing a metal layer on the surface of an electrode immersed in an electrolyte under the influence of voltage. Although known for a long time, until now it has been difficult to observe its course in detail in real time. Thanks to a special flow cell, in which a microscopic volume is separated by two very thin membranes (and one of them is additionally equipped with electrodes), it became possible to track the formation of a platinum-nickel (PtNi) nanolayer. 

The experiment recorded two mechanisms: direct growth of the PtNi layer on the electrode and the formation of nanoparticles in solution and their deposition on the electrode surface, especially where the electron beam reached. More detailed observations showed that the nanostructures have a spherical shape and a dendritic surface. 
In the next stage of the experiment, carried out in cooperation with the Fritz Haber Institute (Max Planck Gesellschaft), the reaction parameters were modified, which allowed for the recording of nucleation and the growth and dissolution cycles of nanoparticles. Observations showed that the growth rate prevailed over dissolution, thanks to which a durable layer was created. 

Further studies were conducted in the STXM microscope at the SOLARIS center in Krakow. Although the resolution of STXM is lower than TEM, the STXM microscope allows for more precise chemical analysis. It was determined that the PtNi layer consists of metallic platinum and nickel(II) oxide. 

The research opens up new possibilities for controlled synthesis of nanostructures that can be used in energy, electronics and medicine. The recognition of the importance of the work was the inclusion of a graphic from the publication on the cover of the 40th issue of Nano Letters.

Read more on SOLARIS website

Researchers establish commercially viable process for manufacturing with promising new class of metals

Researchers establish commercially viable process for manufacturing with promising new class of metals

Nanostructured high entropy alloys – metals made from a chaotic mix of several different elements – show a lot of promise for use in industries such as aerospace and automotive because of their strength and stability at high temperatures compared with regular metals. But they are expensive and energy-intensive to produce. Now researchers working with the Canadian Light Source (CLS) at the University of Saskatchewan (USask) have found a much cheaper and easier way to make them, opening the door for commercial applications.

Michel Haché, a materials engineer at the University of Toronto, and colleagues confirmed that electrodeposition is a cost-effective and easily scaled way to create these alloys. Electrodeposition – which involves dissolving metal ions in water then using an electric current to pull them out of the liquid and form solid materials – is the same process that is used to make chrome-plated motorcycle parts. The findings are published in the journal Surface and Coatings Technology.

The U of T group found that alloys made of several different metals – nickel, iron, cobalt, tungsten, and molybdenum – could withstand temperatures up to 500oC, compared with just 270oC for pure nickel, and were stronger and harder than their less-complex counterparts. “We’re using chaos in the material structure to bring out interesting properties,” he says.

Read more on CLS website