ORCID Profile
0000-0003-1940-4649
Current Organisation
Oak Ridge National Laboratory
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Publisher: American Chemical Society (ACS)
Date: 18-04-2016
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 2020
DOI: 10.2172/1784174
Publisher: American Chemical Society (ACS)
Date: 30-04-2013
DOI: 10.1021/JA312030E
Abstract: The structure of SnO2 nanoparticles (avg. 5 nm) with a few layers of water on the surface has been elucidated by atomic pair distribution function (PDF) methods using in situ neutron total scattering data and molecular dynamics (MD) simulations. Analysis of PDF, neutron prompt gamma, and thermogravimetric data, coupled with MD-generated surface D2O/OD configurations demonstrates that the minimum concentration of OD groups required to prevent rapid growth of nanoparticles during thermal dehydration corresponds to ~0.7 monolayer coverage. Surface hydration layers not only stabilize the SnO2 nanoparticles but also induce particle-size-dependent structural modifications and are likely to promote interfacial reactions through hydrogen bonds between adjacent particles. Upon heating/dehydration under vacuum above 250 °C, nanoparticles start to grow with low activation energies, rapid increase of nanoparticle size, and a reduction in the a lattice dimension. This study underscores the value of neutron diffraction and prompt-gamma analysis, coupled with molecular modeling, in elucidating the influence of surface hydration on the structure and metastable persistence of oxide nanomaterials.
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 12-2019
DOI: 10.2172/1784183
Publisher: IOP Publishing
Date: 2023
Abstract: Modification of the structure and morphology of MXene electrodes and the formulation of the electrolytes used in their supercapacitor configurations are significant factors affecting the performance of electrochemical devices. In this study, we investigated the electrochemical performance and ion dynamics of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EmimTFSI], ionic liquid in the presence of acetonitrile (ACN) at different concentrations in Ti 3 C 2 T x MXene supercapacitor. We found an optimum concentration of ACN, at which more cations from the ionic liquid attach to the MXene electrode surface, providing higher electrochemical performance. This higher capacitance is also associated with increased microscopic dynamics of the cation away from the pore wall. These findings give a guideline to optimize the performance of MXene-based supercapacitors using organic solvents-ionic liquid-based electrolyte systems.
Publisher: American Physical Society (APS)
Date: 30-03-2018
Publisher: American Chemical Society (ACS)
Date: 19-03-2013
DOI: 10.1021/JA3125959
Abstract: Atomistic molecular dynamics (MD) simulations were carried out to investigate the local dynamics of polyelectrolyte dendrimers dissolved in deuterium oxide (D2O) and its dependence on molecular charge. Enhanced segmental dynamics upon increase in molecular charge is observed, consistent with quasielastic neutron scattering (QENS) measurements. A strong coupling between the intradendrimer local hydration level and segmental dynamics is also revealed. Compelling evidence shows these findings originate from the electrostatic interaction between the hydrocarbon components of a dendrimer and the invasive water. This combined study provides fundamental insight into the dynamics of charged polyelectrolytes and the solvating water molecules.
Location: United Kingdom of Great Britain and Northern Ireland
Location: Russian Federation
Location: Germany
No related grants have been discovered for Alexander Kolesnikov.