Tag Archives: Tomsk Polytechnic University

Graphene-based material for high-performance supercapacitors

Researchers from Russia and France have developed a new material, based on graphene, that would allow supercapacitors to store more energy according to a January 15, 2021 news item on Nanowerk,

Scientists of Tomsk Polytechnic University jointly with colleagues from the University of Lille (Lille, France) synthetized a new material based on reduced graphene oxide (rGO) for supercapacitors, energy storage devices. The rGO modification method with the use of organic molecules, derivatives of hypervalent iodine, allowed obtaining a material that stores 1.7 times more electrical energy.

Photo: modified rGO supercapacitor electrodes. Courtesy: Tomsk University

A January 15, 2020 Tomsk Polytechnic University press release (also on EurekAlert), which originated the news item, provides more details,

A supercapacitor is an electrochemical device for storage and release of electric charge. Unlike batteries, they store and release energy several times faster and do not contain lithium.

A supercapacitor is an element with two electrodes separated by an organic or inorganic electrolyte. The electrodes are coated with an electric charge accumulating material. The modern trend in science is to use various materials based on graphene, one of the thinnest and most durable materials known to man. The researchers of TPU and the University of Lille used reduced graphene oxide (rGO), a cheap and available material.

“Despite their potential, supercapacitors are not wide-spread yet. For further development of the technology, it is required to enhance the efficiency of supercapacitors. One of the key challenges here is to increase the energy capacity.

It can be achieved by expanding the surface area of an energy storage material, rGO in this particular case. We found a simple and quite fast method. We used exceptionally organic molecules under mild conditions and did not use expensive and toxic metals,” Pavel Postnikov, Associate Professor of TPU Research School of Chemistry and Applied Biomedical Science and the research supervisor says.

Reduced graphene oxide in a powder form is deposited on electrodes. As a result, the electrode becomes coated with hundreds of nanoscale layers of the substance. The layers tend to agglomerate, in other words, to sinter. To expand the surface area of a material, the interlayer spacing should be increased.

“For this purpose, we modified rGO with organic molecules, which resulted in the interlayer spacing increase. Insignificant differences in interlayer spacing allowed increasing energy capacity of the material by 1.7 times. That is, 1 g of the new material can store 1.7 times more energy in comparison with a pristine reduced graphene oxide,” Elizaveta Sviridova, Junior Research Fellow of TPU Research School of Chemistry and Applied Biomedical Sciences and one of the authors of the article explains.

The reaction proceeded through the formation of active arynes from iodonium salts. They kindle scientists` interest due to their property to form a single layer of new organic groups on material surfaces. The TPU researchers have been developing the chemistry of iodonium salts for many years.

“The modification reaction proceeds under mild conditions by simply mixing the solution of iodonium salt with reduced graphene oxide. If we compare it with other methods of reduced graphene oxide functionalization, we have achieved the highest indicators of material energy capacity increase,” Elizaveta Sviridova says.

Here’s a link to and a citation for the paper,

Aryne cycloaddition reaction as a facile and mild modification method for design of electrode materials for high-performance symmetric supercapacitor by Elizaveta Sviridova, Min Li, Alexandre Barras, Ahmed Addad, Mekhman S.Yusubov, Viktor V. Zhdankin, Akira Yoshimura, Sabine Szunerits, Pavel S. Postnikov, Rabah Boukherroub. Electrochimica Acta Volume 369, 10 February 2021, 137667 DOI: https://doi.org/10.1016/j.electacta.2020.137667

This paper is behind a paywall.

Gold nanoparticles used to catalyze biofuel waste and create a useful additive

This work is the result of an international collaboration including Russia (from a May 23, 2017 news item on Nanowerk),

Gold nanoparticles serve as catalysts for obtaining valuable chemical products based on glycerol. Scientists from Tomsk Polytechnic University and their international colleagues are developing gold catalysts to recycle one of the main byproducts of biofuel production. The obtained products are in high demand in medicine, agriculture, cosmetic industry and other sectors.

Scientists from the University of Milano (Italy), the National Autonomous University of Mexico, the Institute of Catalysis and Petrochemistry of Madrid (Spain) and the University of Porto (Portugal) take part in the study of gold nanoparticles.

A May 23, 2027 Tomsk Polytechnic University press release, which originated the news item, expands on the theme,

Today the production of biofuels is an important area in many countries. They can be obtained from a great variety of biomasses. In Latin America it is orange and tangerine peel as well as banana skin. In USA biofuels are produced from corn, in the central part of Russia and Europe – from rape (Brassica napus). When processing these plants into biofuels a large amount of glycerol is formed. Its esters constitute the basis of oils and fats. Glycerol is widely used in cosmetic industry as an individual product. However, much more glycerol is obtained in the production of biofuels – many thousands of tons a year. As a result, unused glycerol merely becomes waste,’ describes the problem Alexey Pestryakov, the Head of the Department of Physical and Analytical Chemistry. ‘Now, a lot of research groups are engaged in this issue as to how to transform excess glycerol into other useful products. Along with our foreign colleagues we offered catalysts based on gold nanoparticles.’

The authors of the research note that catalytic oxidation on gold is one of the most effective techniques to obtain from glycerol such useful products as aldehydes, esters, carboxylic acids and other substances.

‘All these substances are products of fine organic chemistry and are in demand in a wide range of industries, first of all, in the pharmaceutical and cosmetic industries. In agriculture they are applied as part of different feed additives, veterinary drugs, fertilizers, plant treatment products, etc.

Thus, unused glycerol after being processed will further be applied,’ sums up Alexey Pestryakov.

Gold catalysts are super active. They can enter into chemical reactions with other substances at room temperature (other catalysts need to be heated), in some case even under zero. However, gold can be a catalyst only at the nanolevel.

‘If you take a piece of gold, even very tiny, there will be no chemical reaction. In order to make gold become chemically active, the size of its particle should be less than two nanometers. Only then it gets its amazing properties,’ explains the scientist.

As a catalyst gold was discovered not so long ago, in the early 1990s, by Japanese chemists.

To date, TPU scientists and their colleagues are not the only ones who develop such catalysts.

Unlike their counterparts the gold catalysts developed at TPU are more stable (they retain their activity longer).

‘A great challenge in this area is that gold catalysts are very rapidly deactivated, not only during work, but even during storage. Our objective is to ensure their longer shelf life. It is also important to use oxygen as an oxidizer, since toxic and corrosive peroxide compounds are often used for such purposes,’ says Alexey Petryakov.

Here’s a link to and a citation for the paper,

More Insights into Support and Preparation Method Effects in Gold Catalyzed Glycerol Oxidation by Nina Bogdanchikova, Inga Tuzovskaya, Laura Prati, Alberto Villa, Alexey Pestryakov, Mario Farías. Current Organic Synthesis VOLUME: 14 ISSUE: 3 Year: 2017Page: [377 – 382] Pages: 6 DOI: 10.2174/1570179413666161031114833

This paper is behind a paywall. (Scroll down the page to find the article.)