Palladium–carbon composites study represents prospective in electrochemical technologies

A team of scientists based in Siberia has synthesised palladium–carbon nanoparticles that could improve energy sources and support research across further applications.

A team of scientists based in Siberia has synthesised palladium–carbon nanoparticles that could improve energy sources and support research across further applications.

The researchers studied the properties of palladium-carbon nanocomposite powders obtained by a two-stage synthesis method. At the first stage, powder called “carbon condensate” was obtained by spraying in an arc discharge plasma of alternating current in a helium atmosphere. At the second stage, powder oxidation was carried out during its heating in an open crucible while blowing with a mixture of argon and 20 wt.% oxygen. As a result, two parts of powder were obtained from carbon condensate.

According to the chemical composition analysis, the initial carbon condensate contained 79.7% carbon and 18.4% palladium by weight. The lower of two parts, which was black in colour, was found to contain 91.1% carbon and 7.7% palladium, while the upper part, light grey in colour, contained 1.1% carbon and 95.7% palladium.

To determine electrochemical behaviour the team studied the cyclic voltammetry of ethanol oxidation in an alkaline electrolyte using graphite electrodes, onto which the synthesised palladium–carbon nanopowders were deposited. While the chemical composition of the nanocomposite materials affects their properties and electrochemical behaviour, the shape and size of the powder particles also have a significant impact, in addition to other factors.

The strongest performer was the sample which contained the largest amount of palladium, notably consisting of metallic palladium and PdO2 (palladium(II) oxide). This sample showed an order of magnitude increase in the peak current value. The initial sample also showed high electrochemical energy due to the presence of fullerene, an allotrope of carbon characterised by its hollow hexagonal shape and which accounted for 10.1% of the substance by weight.

Today, traditional materials are increasingly being replaced by composite materials in high-tech industries. The latter possess a number of advantages, and rigorous testing in controlled environments allows researchers to find effective compositions that harness the best qualities of multiple different elements. Carbon-based composite materials have significant physical capabilities, and certain composites have a high specific surface area, varied pore sizes, and high electron conductivity. Graphite, an allotrope of carbon, is a widely used carrier of substances that accelerate electrochemical reactions in numerous areas of application, from sensors to energy production.

Palladium is of particular interest to researchers thanks to its unique properties. It has a clearly defined structure, excellent mechanical and thermal stability, and high catalytic activity especially in nanoparticle form, which supports long-term repeated use. The initial powder obtained through arc discharge, which contains 18.4% palladium, and the light grey sample containing 95.7% palladium, merit further research as electrode materials, with potential applications in batteries, contacts in circuits, sensors, catalysts, microelectronics and biomedicine.

The research was funded in part by the Ministry of Science and Higher Education of the Russian Federation. The team of scientists is based in Krasnoyarsk, at the Siberian Federal University and the Krasnoyarsk Science Centre of the Siberian Branch of the Russian Academy of Sciences.

Source: https://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=jtf&paperid=7211&option_lang=eng