• A
  • A
  • A
  • ABC
  • ABC
  • ABC
  • А
  • А
  • А
  • А
  • А
Regular version of the site

New Data Gained on Double Perovskite Oxides

New Data Gained on Double Perovskite Oxides

© Elmar Lackner / Mindat.org

The Journal of Alloys and Compounds has published an article coauthored by the Institute of Solid State Chemistry and Mechanochemistry (the Ural Branch of the Russian Academy of Sciences), the Donostia International Physics Centre, and the HSE Tikhonov Moscow Institute of Electronics and Mathematics on the characteristics of cubic double perovskite oxides. To date, experimental measurements of the minerals’ characteristics have not corresponded to the results of theoretical modelling. The work marks the first time that researchers have set themselves the task of explaining this disparity. The data obtained will allow researchers to improve low-temperature fuel cell technologies—one of the main alternatives to current sources of electricity.

There is growing support among researchers for the use of fuel cells instead of more widely known galvanic batteries. Typical batteries contain limited amounts of substances used to generate electricity—once the battery runs out of fuel, it stops working. In fuel cells, hydrogen fuel mixes with oxygen to generate electricity, heat, and water, with the fuel being fed from outside and oxygen taken from the air. This means that such batteries can operate as long as they have a stable power supply. The only byproduct of the process is water, which makes the cells an environmentally friendly alternative to manganese or zinc-based batteries, which must be disposed of at the end of their life.

Solid oxide fuel cells (SOFCs) are an increasingly promising technology. The cells use a ceramic material (such as zirconium dioxide) as an electrolyte—a medium between positively and negatively charged electrodes.

Advantages of solid oxide fuel cells include high efficiency, reliability, the ability to be powered by different kinds of fuel, and a relatively low cost.

Moreover, unlike other types of fuel cells, SOFCs do not necessarily need to be flat with an electrolyte between electrodes. They can take different forms, such as tubes through which air or fuel flows through the inner side, with another gas flowing along the outer side.

Solid oxide fuel cells also have one main disadvantage: they require high temperatures (around 500–1000°C) to sustain the necessary chemical reactions. Expensive platinum catalysts are required to use SOFCs at lower temperatures, which increases the cost of fuel cells immensely.

For this reason, many researchers have been looking for ways to decrease the operating temperatures of solid oxide fuel cells without compromising the efficiency of their electricity generation. Areas of research in the field include searching for highly active catalysts for the required reactions, the development of techniques to synthesize SOFC components, and the creation of effective materials for electrodes.

Researchers have proposed using perovskite-like minerals as electrolytes with the required properties for industrial application. Perovskites are a class of minerals composed of two negatively charged ions and one positively charged ion attached to one another. The authors proposed using complex oxide of molybdates with the double perovskite structure A2MeMoO6, where A represents calcium, strontium, or barium, and Me represents 3d metals or magnesium.

Compositions in which A = strontium and Me = magnesium or nickel have been identified as the most promising. These oxides exhibit good electrical conductivity under reducing conditions, as well as a tolerance to sulfur and carbon oxide impurities in fuel gas.

Despite their appeal from a practical viewpoint, the properties of double perovskite-like molybdenum oxides such as Sr2Mg1−xNixMoO6 are not fully understood. Experimental measurements of the substances’ properties differ from theoretical predictions derived from computational modelling, which are themselves highly dependent on initial assumptions and the software code used.

The authors of the article have made the first attempt to combine computer modelling of the substance’s electronic spectrum with experimental data of how Sr2Mg1 – xNixMoO6 conducts electric current. The results support the semiconducting nature of Sr2Mg1 – xNixMoO6 conductivity. As in metals, the motion of charged particles in semiconductors generates an electrical current. However, in metals, the presence of free electrons is due to the structure of the substance and the electron bonds in atoms, while the presence of charge carriers in semiconductors is determined by numerous factors, the most important of which are the purity and temperature of the semiconductor. 

The researchers agree that semiconductors can be effectively used as electrolytes in fuel cells thanks to their good electrochemical characteristics and high ion conductivity. They believe that further studies of double perovskite-like oxides will offer new opportunities to use this promising material in various energy technologies.

See also:

Russian Chemists Develop Luminous Pseudosandwich Composed of Rare Earth Metals

A team of Russian researchers has successfully synthesised a new class of complex compounds of rare earth elements. Unlike other lanthanide compounds, the resulting substances are highly soluble in most organic solvents. These novel compounds can find application in organic and organometallic synthesis, as well as in the production of new luminescent materials. The study has been published in Inorganic Chemistry.

Scientists Devise Cheaper and Easier Method for Synthesising Layered Rare Earth Hydroxides—'Chemical Sandwiches’

Researchers at HSE University and the RAS Kurnakov Institute of General and Inorganic Chemistry have developed a simplified and cost-effective method for synthesising layered rare earth hydroxides using propylene oxide. This reagent helps streamline the process and reduce its duration by several hours. In the future, this method is expected to facilitate the synthesis of various hydroxide-based hybrid materials, including photocatalysts for water purification and luminescent materials for solid-phase thermometers. The paper has been published in the Russian Journal of Inorganic Chemistry.

‘Digital Chemistry Is the Cutting Edge of Science’

In 2024, a new track ‘Digital Chemistry and Artificial Intelligence Technologies’ will open within the Bachelor’s programme in Chemistry. This track will offer courses in digital engineering, multi-scale modelling, chemometrics, and chemoinformatics, as well as big data and artificial intelligence technologies. Specialists from HSE University, Zelinsky Institute of Organic Chemistry, Moscow Institute of Physics and Technology, and Peter the Great St Petersburg Polytechnic University will be among the lecturers.

Chemists Improve Membranes for Water Treatment and Desalination

Chemists at HSE University, Kurnakov Institute of General and Inorganic Chemistry, and the University of Science and Technology of China have developed membranes with enhanced properties. The researchers experimentally revealed the impact of various factors on the desalination process and on the selectivity of ion separation. According to the study authors, their research will enable a more precise prediction of the properties of new ion-exchange membranes used in water treatment and desalination. The study findings have been published in Desalination.

‘The Main Thing Is to Try to Learn New Things by Any Honest Means’

Chemist Polina Yurova works in the same laboratory of the IGIC RAS that she first visited as a tenth grader. In this interview with the Young Scientists of HSE University project, she spoke about the creation of ion-exchange membranes, the ‘hair’ of black holes and her favourite Moscow park.

Russian Scientists Present New Application for Nanophotonic Sensor

A joint research team from HSE, Skoltech, MPGU and MISIS has developed a compact sensor for biochemical analysis, opening up a new frontier in the development of the ‘lab-on-a-chip’. Using bovine serum albumin film as an example, the researchers proved that the chip surface can be adapted for selective analysis of multicomponent solutions. Along with enabling accurate blood tests with only 3 to 5 microliters of blood, the chip will help doctors to detect specific disease markers. The study was published in Analytical Chemistry.

Scientists Create Uniquely Stable Trimeric Model of Coronavirus Spike Transmembrane Domain

A team of Russian scientists, including HSE MIEM researchers, have presented a 3D model of SARS-CoV-2 S-protein transmembrane (TM) domain. Previously, the TM domain had only been believed to anchor the S-protein in its viral membrane without being involved in rearrangement and fusion with the host cell. Yet according to recent studies, the TM domain appears to have a function in the transmission of genetic information, but its role is not yet fully understood. The researchers believe that the model they have created can contribute to a better understanding of viral mechanisms and potentially lead to the development of novel antiviral drugs. The study has been published in the International Journal of Molecular Sciences.

Fluoride Additive to Boost Production of Sedatives

Russian researchers from HSE University and the Russian Academy of Sciences Nesmeyanov Institute of Organoelement Compounds have come up with a new method of enhancing the chemical reaction involved in producing gamma-aminobutyric acid (GABA) analogues used in sedative drugs. Adding fluoride to the catalyst more than doubled the yield of the pure product and increased the total reaction yield by 2.5 times. This approach is expected to make the production of certain drug components more efficient and less costly. The study has been published in the Journal of Organic Chemistry.

HSE University Launches New Master’s Programme in Chemistry

In 2023, the first Master's programme 'Chemistry of Molecular Systems and Materials' at the HSE Faculty of Chemistry will enrol students. Half of the study time will be devoted to research projects in the field of modern fundamental and applied research on the topics studied at five institutes of the Russian Academy of Sciences. Dmitrii Roitershtein, Academic Supervisor of the programme and Associate Professor at the Joint Department of Organic Chemistry with the RAS Zelinsky Institute of Organic Chemistry, spoke about the programme to the HSE News Service.

Russian Chemists Improve Seawater Desalination Membrane

A team of researchers of the HSE Faculty of Chemistry  Joint Department of Inorganic Chemistry and Materials Science with the RAS Kurnakov Institute of General and Inorganic Chemistry have designed a novel type of hybrid ion-exchange membrane. Such membranes can be used to produce drinking water from seawater, which is particularly relevant for areas with access to the sea and a shortage of drinking water. The study is published in Desalination.