Tag: TXM

Comprehensive study of strontium hexaferrite platelets

Comprehensive study of strontium hexaferrite platelets

Researchers have synthesized and studied by a combination of soft X-ray techniques platelets of strontium hexaferrite allowing them to establish the differences and similarities between their synthesized nanostructures and commercial powders.

Most of the experiments have been performed within a collaboration among three beamlines of the ALBA Synchrotron.
Ferrites are ceramic materials usually made of large proportions of iron oxide (Fe2O3, rust) blended with small proportions of other metallic elements. These materials do not conduct electricity because they are insulators; and they are ferromagnetic, which means they can easily be magnetized or attracted to a magnet.

Strontium ferrites (SFO, SrFe12O19) in particular have a large magnetocrystalline anisotropy that gives it a high coercitivity, meaning that it is difficult to demagnetize. Since its discovery in the mid-20th century, this hexagonal ferrite has become an increasingly important material both commercially and technologically, finding a variety of uses and applications because of its low cost and toxicity. SFO has been used for permanent magnets, recording media, in telecommunications, and as a component in microwave, high-frequency and magneto-optical devices. Also, because they can be powdered and formed easily, they are finding their applications into micro and nano-types systems such as biomarkers, bio diagnostics and biosensors.

>Read more on the ALBA website

Synchrotron light for deciphering Friedreich’s Ataxia

Synchrotron light for deciphering Friedreich’s Ataxia

A team from the Germans Trias i Pujol Research Institute (IGTP) in Badalona is performing an experiment at the ALBA Synchrotron to obtain for the first time 3D images of cells with this disease.

Friedreich’s ataxia affects more than 3,000 people in Spain, causing serious mobility problems and other severe illnesses such as heart disease. At present there is no treatment to prevent or cure the disease.

Friedreich’s ataxia is a rare neurodegenerative disease that progressively damages mobility, balance and coordination. It is an inherited disease, caused by a genetic mutation, that can appear when both parents are carriers. A research group from the Germans Trias i Pujol Research Institute (IGTP), at the Can Ruti Campus in Badalona, led by Dr. Antoni Matilla, is looking into the causes and possible treatments for this disease that results in high disability and an important decrease in the patients’ quality of life.

“Today there is no treatment or cure for Friedreich’s ataxia. It is necessary to try to understand how the disease develops in order to propose therapeutic solutions”, says Dr. Ivelisse Sánchez, co-Principal Investigator of this project at the Neurogenetics Unit of the IGTP. Researchers are now analysing donors’ cells in the ALBA Synchrotron to see the changes caused by the disease.

>Read more on the ALBA website

Image: Dr. Ivelisse Sánchez, co-Principal Investigator of the project, and pre-doctoral researcher Eudald Balagué at the MISTRAL beamline.

Cause of cathode degradation identified for nickel-rich materials

Cause of cathode degradation identified for nickel-rich materials

Combination of research methods reveals causes of capacity fading, giving scientists better insight to design advanced batteries for electric vehicles

A team of scientists including researchers at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and SLAC National Accelerator Laboratory have identified the causes of degradation in a cathode material for lithium-ion batteries, as well as possible remedies. Their findings, published on Mar. 7 in Advanced Functional Materials, could lead to the development of more affordable and better performing batteries for electric vehicles.

Searching for high-performance cathode materials
For electric vehicles to deliver the same reliability as gas vehicles they need lightweight yet powerful batteries. Lithium-ion batteries are the most common type of battery found in electric vehicles today, but their high cost and limited lifetimes are limitations to the widespread deployment of electric vehicles. To overcome these challenges, scientists at many of DOE’s national labs are researching ways to improve the traditional lithium-ion battery.

>Read more on the NSLS-II at Brookhaven Lab website

Image: Members of the Brookhaven team are shown at NSLS-II’s ISS beamline, where part of the research was conducted. Pictured from front to back are Eli Stavitski, Xiao-Qing Yang, Xuelong Wang, and Enyuan Hu.

Direct Observation of the Kinetics of Gas–Solid Reactions

Direct Observation of the Kinetics of Gas–Solid Reactions

… using in-situ kinetic and spectroscopic techniques.

Copper oxide is a widely used adsorptive material that removes trace amounts of H2S from various process streams via chemical reaction to form copper sulfide. At room temperature the thermodynamics favor a near complete conversion of CuO to copper sulfide in the presence of H2S. However, in application, the extent of conversion of the CuO to copper sulfide during reaction can be influenced by many factors, including the initial crystalline state of the CuO, and the rate at which solid products accumulate on the reactive surfaces or within pores of the CuO particles. This incomplete utilization of CuO is problematic for industrial applications because it typically leads to oversized equipment and/or frequent process shutdowns. Developing fundamental insight at the atomic scale for this reaction could overcome these limitations by providing a rational basis for the design of new materials and by leading to predictive models that allow for current materials to be operated toward their thermodynamic limits. Thus, experiments that combine reaction kinetic testing while also simultaneously capturing chemical and structural changes in the solid phase at multiple length scales are necessary to elucidate the fundamentals of these reactions at various length scales.

Previous studies were successful in semi-quantitatively relating properties of materials to performance in fixed-bed systems, however, differences in performance were often attributed to physical properties at the >10 mm scale (e.g., surface area, pore volume, bulk density). The effects of molecular scale material characteristics (e.g., microscopic shape, metal oxide crystallite size, and surface composition) were rarely investigated, thus, it is difficult to extend the conclusions from these studies across a broad range of conditions and materials.

>Read more on the SSRL at SLAC website

Image (extract): (A) CuO and CuS concentration maps derived from XANES analysis of TXM images of individual CuO particle during reaction with 1000 ppm H2S. (B) Fractional conversion versus time (derived from linear combination fitting of Cu K-edge XANES) of fixed beds of CuO particles consisting of 2 different crystallite sizes (red circles are 2.8 nm and blue squares are 28 nm) and of individual CuO particles. See the entire figure here.