Electrochemical, photoelectrochemical and spectroelectrochemical characterization of nanomaterials

0482903 - ÚFCH JH 2018 CZ eng D - Dizertace
Lásková, Barbora
Electrochemical, photoelectrochemical and spectroelectrochemical characterization of nanomaterials.
Ústav fyzikální chemie J. Heyrovského AVČR, v. v. i. Obhájeno: Přírodovědecká fakulta (PřF), Universita Karlova. 16. 10. 2017. - Praha: Přírodovědecká fakulta (PřF), Universita Karlova, 2017. 51 s.
Institucionální podpora: RVO:61388955
Klíčová slova: electrochemistry * photoelectrochemistry * spectroelectrochemistry
Kód oboru RIV: CG - Elektrochemie
https://is.cuni.cz/webapps/zzp/detail/94292/27757406/?q=%7B%22______searchform___search%22%3A%22Bou%5Cu0161a%22%2C%22______searchform___butsearch%22%3A%22Vyhledat%22%2C%22______facetform___facets___workType%22%3A%5B%22IP%22%5D%2C%22PNzzpSearchListbasic%22%3A%221%22%7D&lang=cs

Titanium dioxide (TiO2) and spinel Li4Ti5O12 belong to widely studied semiconducting metal oxides. Nanocrystalline TiO2 and Li4Ti5O12 are attractive materials for applications in Li-ion batteries and the former also for photoelectrochemical solar cells. Moreover, spinel Li4Ti5O12 could be a promising material for Na-ion batteries too, because of possible accommodation of larger Na+ ions (compared to Li+). The nanocrystalline TiO2 anatase with a predominant {001} facet was studied electrochemically by cyclic voltammetry of Li+ insertion and by chronoamperometry and compared with anatase materials with dominating {101} facet. Both voltammetric and chronoamperometric diffusion coefficients and activation energies proved higher activity of anatase {001} nanosheets toward Li+ insertion than that of the usual anatase nanoparticles exposing the {101} facet. Subsequently, the flatband potential and electron kinetics of TiO2 anatase nanocrystals with mostly exposed facet {101} or {001} were compared. The anatase {001} nanoplatelets exhibited more negative flatband potential, higher chemical capacitance and longer electron lifetime than anatase {101} nanoparticles. The Li+ insertion into TiO2 anatase nanoparticles was studied by Raman spectroscopy and by in situ Raman spectroelectrochemistry. Four combinations of isotopologues, namely 6/7LixTi16/18O2 (x is the insertion coefficient), were prepared and studied. The combination of experimental and theoretical Raman frequencies with the corresponding isotopic shifts brings new inputs for still open questions about the Li-insertion into TiO2 (anatase). The cyclic voltammograms of Li+ insertion into TiO2 (B) and anatase provided information about capacitive contributions to the overall charge of Li-storage.
Trvalý link: http://hdl.handle.net/11104/0278293