The current study focuses on the production of biochars derived from aquatic plants, specifically red seaweed Ahnfeltia and seagrass Zostera and Ruppia, found in brackish lagoons in the Sea of Okhotsk, Sakhalin Island. These biochars were obtained through a stepwise pyrolysis process conducted at temperatures of 500 and 700 °C. The characteristics of the biochars, including their elemental composition, specific surface area, and particle size distribution, were found to be influenced by both the type of biomass used and the pyrolysis temperature. The primary objective of this research was to investigate the potential of these biochars to be used as negative electrodes for lithium ion batteries. Among the various samples we tested, the biochar derived from the macroalgae Ahnfeltia tobuchiensis, produced at 700 °C, exhibited the highest carbon content (70 at%) and nitrogen content (>5 at%). The reversible capacity of this particular biochar was measured to be 391 mAh g⁻¹ during the initial cycles and remained relatively stable at around 300 mAh g⁻¹ after 25 cycles. These findings suggest that biochars derived from aquatic plants have the potential to be utilized as effective electrode materials in lithium ion batteries. The specific properties of the biochar, such as its elemental composition and surface area, play a significant role in determining its electrochemical performance. Further research and optimization of the pyrolysis conditions may lead to the development of biochar-based electrodes with improved capacity and cycling stability, thereby contributing to the advancement of sustainable and environmentally friendly energy storage systems.

Electrocatalysts based on platinized titania modified with ruthenia (0–9 mol %) were studied. The synthesized materials were investigated as working electrodes in potentiometric sensors sensitive to...

The electrocatalytic activity of materials in the 10% Pt/Ti1– xRu xO2–δ system, where x= 0–0.3 (0 ≤ Ru ≤ 30 mol %), in the reactions of hydrogen electrooxidation in the presence of CO is studied in...

The work is devoted to the study of the influence of synthesis conditions on the properties of water-insoluble rubidium salts of phosphotungstic acid (PTA). Such heteropoly compounds have a wide range of applications, including in the field of electrocatalysts and solid electrolytes for various electrochemical devices. The acid salts of PTA with high activity of acid sites on the particle surface are of particular interest. It is known that the properties of water-insoluble PTA salts strongly depend on synthesis conditions, such as the ratio of reagents, temperature, concentrations, and other parameters. The work examines the influence of the ratio and concentration of reagents on the sizes of crystallites and agglomerates, specific surface area (SSA), porosity, water content, and ionic conductivity of the synthesized PTA salts. The SSA value of the obtained samples varied in the range of 84–123 m² g⁻¹, and the ionic conductivity was 13–90 mS cm⁻¹ at room temperature and 75% RH. An increase in the acid concentration and the degree of proton substitution led to an increase in SSA, accompanied by an increase in particle sizes without changing the size of crystallites. The results of the work may be useful for the development of new materials based on the obtained salts in many fields, including hydrogen energy.

The carbon films formed by accelerated C₆₀ ion deposition are investigated by transmission electron microscopy and X-ray photoelectron spectroscopy. It is demonstrated that amorphous carbon films are formed at an ion-beam energy of 7 keV and a temperature of the substrate of 100–200°C. Substrate temperature increase to 300°C results in the formation of nanocomposite films consisting of graphite nanocrystals embedded in an amorphous carbon matrix. The presence of double- and triple-charged C₆₀ ions with an energy of 14 and 21 keV respectively in the beam results in a decrease in the temperature of formation of the nanocomposite to 200°C. As the result of analysis of the data collected from various sample depths by X-ray photoelectron spectroscopy and Auger-electron spectroscopy, it is found that the sp³/sp² ratio in the surface layers is higher than in the sample bulk, both in the case of a monoenergetic 7 keV beam, and in the presence of multicharged high-energy ions in the beam. If high-energy ions are present in the beam, then the sp³/sp² ratio is higher and depends, in a complex way, on the temperature of deposition. The maximum amount of sp³ bonds in the surface layers is found at a temperature of deposition of 350°C and is equal to 88%. The water drop contact angle for this film is 96°, which is similar to the contact angle of the diamond surface.

The electrocatalysts based on platinized TiO₂(Ru) oxides with different ruthenium content are studied as the working electrode in solid-state potentiometric sensors for H₂ and CO. Increasing the ruthenium content does not affect the size of platinum particles, but reduces its content in the metallic state. The results of X-ray diffraction, X-ray fluorescence, and scanning electron microscopic studies are presented. The synthesized electrocatalysts are tested as the working-electrode materials in hydrogen and carbon monoxide sensors for the gas concentration in the air flow from 1 to 50 000 ppm. The characteristics of the sensors are shown to depend on the oxide support composition and structure. The electrocatalysts with the rutile structure are recommended for the practical use; the ruthenium content is determined by the range of analyzed CO concentrations.