Efficiency threshold of carbon layer growth in Li4Ti5O12/C composites

The core-shell morphology study is crucial for composite materials, comprised of a low conductive core with a highly conductive thin carbon shell. The study analyzed carbon morphology evolution for the two series of Li4Ti5O12/C samples with carbon content increasing from 0.9 to 5.6 wt%. The conventional X-Ray Photoelectron Spectroscopy (XPS) study allowed us to conclude about the efficiency threshold of carbon layer growth over lithium titanate core for two carbon deposition methods - both sucrose and acetylene decompositions. Although the carbon layer thickness is increasing with carbon concentration growth in LTO/C composites, the efficiency of carbon coverage was shown to decrease with the threshold carbon concentrations about 1-2%. The chemical bonding analysis based on the same XPS data was used for C@LTO interface characterization. The proposed approach can be used for optimization of producing different composites with core-shell structure (carbon-based composites, materials with protective layers, and materials with gradient core-shell structure). © The Author(s) 2018. Published by ECS.This work was performed within the state task no. 3.6115.2017/8.9 of the Ministry of Education and Science of the Russian Federation and supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU and JSC Eliont were used. Authors thanks Vasily Lebedev and Alexander Esin for fruitful discussions

Shape Transformation of Copper Nanoparticles in Water Colloid during Aging

The shape transformation of copper nanoparticles in water colloid by the aging was demonstrated. Initial spherical nanoparticles synthesized by laser ablation of Cu target in water had been aged at temperatures in the range 25-85. The aging temperature notably influenced the nanoparticles shape.The work was supported by Russian Science Foundation (project 21-72-00116; https://rscf.ru/project/21-72-00116). The equipment of the Ural Center for Share Used «Modern Nanotechnologies» Ural Federal University (Reg. 2968) was used

Efficiency of carbon layer growth in Li4Ti5O12/C composites studied by XPS and Raman spectroscopy

The understanding of carbon layer formation is very important for core-shell composite electrodes, comprised of a low conductive core (active material) with a thin carbon shell (conductive additive). In this work we analyze the carbon morphology evolution for the two series of Li4Ti5O12/C samples with carbon content increasing from 0.9 to 5.6 wt%

Synthesis of Decorated Carbon Structures with Encapsulated Components by Low-Voltage Electric Discharge Treatment

Abstract: Polycondensation of complexes of chloromethanes with triphenylphosphine by the action of low-voltage electric discharges in the liquid phase gives nanosized solid products. The elemental composition involving the generation of element distribution maps (scanning electron microscopy–energy dispersive X‑ray spectroscopy mapping) and the component composition (by direct evolved gas analysis–mass spectrometry) of the solid products have been studied. The elemental and component compositions of the result-ing structures vary widely depending on the chlorine content in the substrate and on the amount of triphenylphosphine taken. Thermal desorption analysis revealed abnormal behavior of HCl and benzene present in the solid products. In thermal desorption spectra, these components appear at an uncharacteristically high temperature. The observed anomaly in the behavior of HCl is due to HCl binding into a complex of the solid anion HCI-2 with triphenyl(chloromethyl)phosphonium chloride, which requires a relatively high temperature (up to 800 K) to decompose. The abnormal behavior of benzene is associated with its encapsulated state in nanostructures. The appearance of benzene begins at 650 K and continues up to temperatures above 1300 K. © 2022, The Author(s).The work was carried out with the equipment of the "Modern Nanotechnologies" Ural Shared-Use Center at the Ural Federal University. The study was supported by the Russian Foundation for Basic Research, project no. 18-29-24008

Uncommon 2D Diamond-like Carbon Nanodots Derived from Nanotubes: Atomic Structure, Electronic States and Photonic Properties

In this article, we report the results of relatively facile fabrication of carbon nanodots from single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT). The results of X-ray photoelectron spectroscopy (XPS) and Raman measurements show that the obtained carbon nanodots are quasi-two-dimensional objects with a diamond-like structure. Based on the characterization results, a theoretical model of synthesized carbon nanodots was developed. The measured absorption spectra demonstrate the similarity of the local atomic structure of carbon nanodots synthesized from single-walled and multi-walled carbon nanotubes. However, the photoluminescence (PL) spectra of nanodots synthesized from both sources turned out to be completely different. Carbon dots fabricated from MWCNTs exhibit PL spectra similar to nanoscale carbon systems with sp3 hybridization and a valuable edge contribution. At the same time nanodots synthesized from SWCNTs exhibit PL spectra which are typical for quantum dots with an estimated size of ~0.6-1.3 nm.Comment: 22 pages, 9 figures, to appear in PCC

Polarization reversal in lithium niobate with compositional gradients

The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (Project № 19-12-00210)

Charged domain walls in lithium tantalate with compositional gradients produced by VTE process

The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (Project № 19-12-00210)

SHAPE TRANSFORMATION OF COLLOIDAL NANOPARTICLES, PRODUSED BY LASER ABLATION OF ZINC IN WATER

We investigated the growth of zinc-based colloidal nanoparticles. The initial nanoparticles were produced by laser ablation of bulk Zn target in water. Rods grew in the colloid as a result of the long heating up to 90 ℃. Plates formed during the long liquid-air interaction at ambient conditions.Исследование выполнено за счет гранта Российского научного фонда (No 21-72-00116, https://rscf.ru/project/21-72-00116), с использованием оборудования УЦКП «Современные нанотехнологии» УрФУ