Browsing by Author "Schrebler, Ricardo"

Now showing 1 - 7 of 7
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    An electrochemical deposition route for obtaining alpha-Fe2O3 thin films - II. EQCM study and semiconductor properties
    (ELECTROCHEMICAL SOC INC, 2007) Schrebler, Ricardo; Llewelyn, Cynthia; Vera, Francisca; Cury, Paula; Munoz, Eduardo; del Rio, Rodrigo; Meier, Humberto Gomez; Cordova, Ricardo; Dalchiele, Enrique A.
    The electrochemical formation of hematite (alpha-Fe2O3) precursor thin films (oxyhydroxide iron compounds), onto gold substrates in an aqueous solution of Fe (III) + KF + H2O2 was investigated in situ using an electrochemical quartz crystal microbalance (EQCM) and voltammetric techniques. Nanostructured alpha-Fe2O3 obtained after annealing of oxyhydroxide iron compounds thin films have been prepared onto SnO2/F covered glass substrates through a potential cycling procedure in this electrolytic bath. Photoelectrochemical measurements, carried out in 0.1 M NaOH + 0.05 M KI electrolyte at pH 13, show an n-type behavior, a flatband potential of -1.08 V vs saturated mercury/mercury sulfate reference electrode, and an apparent donor density of 1.26 X 10(19) cm(-3) at 1 kHz. (C) 2007 The Electrochemical Society.
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    CdTe quantum dots modified electrodes ITO-(Polycation/QDs) for carbon dioxide reduction to methanol
    (ELSEVIER, 2020) Guzman, Diego; Isaacs, Mauricio; Tsukuda, Tatsuya; Yamazoe, Seiji; Takahata, Ryo; Schrebler, Ricardo; Burgos, Ana; Osorio Roman, Igor; Castillo, Francisco
    The present work describes the characterization by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques of ITO modified electrodes with electrostatic assemblies (Polycation/Quantum Dots) and their use in the electro- and photoelectrocatalytic reduction of CO2. These assemblies were prepared with polycations poly-diallyldimethylammonium (PD) and poly-(2-trimethylammonium) ethyl methacrylate (PM) and nanocrystals of CdTe of 2.77 nm (Q2). The size of the nanocrystals was controlled by the synthesis reflux time and incorporated by electric field directed Layer-by-Layer assembly method (EFDLA). The polycations were characterised by NMR measurements; showing important effects on the electrostatic assemblies. PM modified electrodes, with its lower rigidity, exhibited less roughness than the PD modified electrodes, 8.0 nm versus 32.8 nm, and higher heterogeneity in its surface composition. Higher resistance to the charge transfer and time constants were obtained with PMQ2 modified electrode, 63.8 Omega cm(-2) and 2.69 ms versus 49.30 Omega cm(-2) and 1.3 ms for PDQ2. The electro- and photoelectro properties for CO 2 reduction were studied through j-E curves and potential controlled electrolysis. Modified surfaces were active toward the reduction of CO2, with a positive shift of the activity between darkness and irradiation conditions, 0.050 V with PDQ2 and 0.450 V with PMQ2. The main product of the CO2 reduction was CH3OH, with traces of CO and HCOOH. The PM modified electrodes with QDs of 2.77 nm presented a selective behaviour for the production of CH3OH.
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    Enhanced photostability of cuprous oxide by lignin films on glassy carbon electrodes in the transformation of carbon dioxide
    (2018) Landaeta Campos, Esteban Alonso; Schultz, Zachary D.; Burgos, Ana; Schrebler, Ricardo; Isaacs Casanova, Mauricio
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    MODIFICATION OF BORON DOPED DIAMOND ELECTRODES WITH GLUCOSE OXIDASE, CHARACTERIZATION BY ELECTROCHEMICAL TECHNIQUES
    (SOC CHILENA QUIMICA, 2011) Del Rio, Rodrigo; Armijo, Francisco; Schrebler, Ricardo; Del Canto, Gabriela; Vergara, Claudia; Gutierrez, Cesar
    In this work, we report the effect of the direct successive modifications with Glucose oxidase onto boron doped diamond electrode (BDD). The modification due to the enzyme adsorption, on the potentiodynamic response of the electrode, was evaluated using Fe(CN)(6)(4-/3-) red-ox couple on the electrolyte and the Delta Ep variations were related with the number of modifications. Contact angle measurements and the electrochemical impedance spectra were also used to characterized the modifications and they showed variations in the same way that the potentiodynamic data.
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    Modification of composites of block copolymers-gold nanoparticles with enzymes and their characterization by electrochemical techniques
    (SPRINGER, 2011) Del Rio, Rodrigo; Armijo, Francisco; Schrebler, Ricardo; Gutierrez, Cesar; Amaro, Andrea; Biaggio, Sonia R.
    In this work, the poly(styrene-vynil pyridine) block copolymer was used as a porous pattern to study the electrodeposition of gold inside the pores, as a new method to obtain gold nanoparticles. The porous pattern left by the copolymer film onto a conductive glass surface was characterized by atomic force microscopy (AFM), evidencing pores of 30 nm diameter. After the electrodeposition, 30 nm diameter gold nanoparticles were obtained and they were characterized by cyclic voltammetry (CV) and AFM, and then used to study the adsorption of glucose oxidase enzyme. The adsorption process of glucose oxidase on gold nanowires was investigated by CV and electrochemical impedance spectroscopy. The morphological and capacitance results indicate that the block copolymer-gold nanoparticle composite seems to be a good candidate to design biosensors and immunosensors.
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    Preparation of palladium thin films and their usefulness as modified electrodes
    (2002) Tejos, Marisol; Schrebler, Ricardo; Díaz Alzamora, Fernando Raúl; Valle de la Cortina, María Angélica del
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    Solvent effect on the nucleation and growth mechanisms of poly(thiophene)
    (2002) Valle Delaware la Cortina, María Angélica del; Cury, P.; Schrebler, Ricardo