ORCID Profile
0000-0003-4414-5431
Current Organisation
Universidade de São Paulo
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Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 2015
Publisher: The Electrochemical Society
Date: 16-04-2010
DOI: 10.1149/1.3422580
Abstract: The semiconducting properties of passive films formed on AISI304 steel, thermally at 400ºC or anodically in a borate buffer solution, were comparatively studied by capacitance measurements and the usual Mott-Shottky (MS) approach in an aqueous borate buffer solution of pH 9.2 and in BMMITFSI, a room temperature ionic liquid. This ionic liquid was used due to its wide electrochemical window of circa 4.3 V, enabling the verification of the accuracy of the MS approach. Two regions corresponding to p and n-type semiconduction were observed in both electrolytes, but calculated dopant concentrations were not always equal. In the ionic liquid a second deeper donor level was always present, which must be further investigated.
Publisher: Elsevier BV
Date: 02-2013
Publisher: Hindawi Limited
Date: 12-2012
Publisher: Elsevier BV
Date: 11-2014
Publisher: Sociedade Brasileira de Quimica (SBQ)
Date: 2013
Publisher: Elsevier BV
Date: 2015
Publisher: FapUNIFESP (SciELO)
Date: 2010
Publisher: Elsevier BV
Date: 09-2009
DOI: 10.1016/J.JCIS.2009.05.050
Abstract: Highly stable and crystalline V(2)O(5) nanoparticles with an average diameter of 15 nm have been easily prepared by thermal treatment of a bariandite-like vanadium oxide, V(10)O(24) x 9 H(2)O. Their characterization was carried out by powder X-ray diffractometry (XRD), Fourier transform infrared (FT-IR) and Raman spectroscopies, and transmission electron microscopy (TEM). The fibrous and nanostructured film obtained by electrophoretic deposition of the V(2)O(5) nanoparticles showed good electroactivity when submitted to cyclic voltammetry in an ionic liquid-based electrolyte. The use of this film for the preparation of a nanostructured electrode led to an improvement of about 50% in discharge capacity values when compared with similar electrodes obtained by casting of a V(2)O(5) xerogel.
Publisher: Elsevier BV
Date: 03-2013
Publisher: Elsevier BV
Date: 03-2007
Publisher: American Chemical Society (ACS)
Date: 22-02-2008
DOI: 10.1021/LA702347X
Abstract: Thin films of MnO(2) nanoparticles were grown using the layer-by-layer method with poly(diallyldimetylammonium) as the intercalated layer. The film growth was followed by UV-vis, electrochemical quartz crystal microbalance (EQCM), and atomic force microscopy. Linear growth due to electrostatic immobilization of layers was observed up to 30 bilayers, but electrical connectivity was maintained only for 12 MnO(2)/PPDA bilayers. The electrochemical characterization of this film in 1-butyl-2,3-dimethyl-imidazolium (BMMI) bis(trifluoromethanesulfonyl)imide (TFSI) (BMMITFSI) with and without addition of a lithium salt indicated a higher electrochemical response of the nanostructured electrode in the lithium-containing electrolyte. On the basis of EQCM experiments, it was possible to confirm that the charge compensation process is achieved mainly by the TFSI anion at short times (<2 s) and by BMMI and lithium cations at longer times. The fact that large ions like TFSI and BMMI participate in the electroneutrality is attributed to the redox reaction that occurs at the superficial sites and to the high concentration of these species compared to that of lithium cations.
Publisher: American Chemical Society (ACS)
Date: 06-12-2013
DOI: 10.1021/LA4038809
Abstract: Water uptake by thin films composed of the poly(ionic liquid) poly[diallyldimethylammonium bis(trifluoromethanesulfonyl)imide] (PDDATf2N) and the ionic liquid N,N-butylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr1.4Tf2N) was studied with a quartz crystal microbalance with dissipation. The data obtained for films with different compositions during the passage of dry and wet N2 flow through the films were simulated with the Kevin-Voigt viscoelastic model for assessment of the mass of uptake water as well as the viscoelastic parameters. Our results show that the ionic liquid acts as a plasticizer, reducing the rigidity of the film and decreasing the capacity of water uptake. Introduction to a Li salt (LiTf2N) increases the water uptake capacity and also affects both elastic and viscous parameters due to aggregation among the ions from the ionic liquid and Li(+). However, due to the preferable interaction of Li(+) ions with water molecules, these aggregates are broken when the film is hydrated. In short, the presence of water in such films affects their mechanical properties, which can reflect in their performances as solid state electrolytes and ion-conducting membranes for electrochemical applications.
No related grants have been discovered for Roberto Manuel Torresi.