Voltammetric stabilization of electrofaceted (100)-type platinum electrodes in acidic solutions

1988 ◽  
Vol 66 (9) ◽  
pp. 2259-2267 ◽  
Author(s):  
Sara Alfonsina Dora Aldabe De Bilmes ◽  
María Cristina Giordano ◽  
Alejandro Jorge Arvia
Keyword(s):  
Competitive Adsorption ◽  
Co Adsorption ◽  
Surface Modifications ◽  
Electrolyte Composition ◽  
Potential Range ◽  
Platinum Electrodes ◽  
Potential Cycling ◽  
Acidic Solutions ◽  
Solution Interface ◽  
Pt Electrodes

The voltammetric stabilization of electrofaceted (100)-type Pt electrodes prepared from polycrystalline Pt by fast repetitive triangular potential cycling are followed by conventional voltammetry in the H-electroadsorption/electrodesorption potential range in either 1 M H2SO4 (0 to 35 °C) or 0.5 M HClO4 (−2 to 35 °C). The influence of CO adsorption on the stabilized voltammetric profile is also considered. Depending on the potential cycling used in conventional voltammetry, two well-defined stabilized profiles at 0.1 V/s in the H-electroadsorption/electrodesorption range can be obtained, namely, that corresponding to the H-adsorption stabilized electrofaceted (100)-type Pt, and that related to the O-adsorption stabilized electrofaceted (100)-type Pt.The changes in the conventional voltammetric profiles can be interpreted in terms of surface modifications basically associated with either adsorption or electroadsorption processes. The influence of the anion (electrolyte composition) prevailing in solution is accounted for in terms of a competitive adsorption between anions and H-adatoms. The influence of temperature in the range covered by this work is smaller than that of the structure of the solution at the electrode/solution interface.

Structural and Electrochemical Studies on Thin-Film Yttria-Doped Zirconia Electrolytes for Microscale Solid Oxide Fuel Cells

2008 ◽  
Author(s):  
Alex C. Johnson ◽  
Shriram Ramanathan
Keyword(s):  
Thin Film ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Platinum Electrodes ◽  
Electrochemical Studies ◽  
Oxide Fuel ◽  
Conductivity Measurements ◽  
Fuel Cell Performance ◽  
Pt Electrodes

We report in-plane and through-plane conductivity measurements of dense YSZ films varying in thickness from 20 to 200 nm. In-plane measurements were performed on YSZ films grown on silicon wafers coated with SiO2 or Si3N4. Micro-fabricated strips with Pt electrodes in various geometries were used to obtain conductivity as a function of temperature from 200 – 600 °C in a custom-designed micro-probe station. These films have activation energies, which vary from 0.77 to 1.09 eV. Their absolute conductivity is lower compared with other reports. Through-plane and fuel cell measurements were performed by depositing YSZ on a nitrided silicon wafer, then etching through the wafer and depositing porous platinum electrodes on both sides [6,7]. We discuss the electrochemical conduction studies in detail along with fuel cell performance and correlation with electrode microstructure.

scholarly journals Beam Effects During In Situ Potential Cycling and Imaging of Sulfuric Acid and Platinum Electrodes

2015 ◽  
Vol 21 (S3) ◽  
pp. 1935-1936 ◽  
Author(s):  
Todd Brintlinger ◽  
Corey Love ◽  
Olga Baturina
Keyword(s):  
Sulfuric Acid ◽  
Platinum Electrodes ◽  
Potential Cycling

A study of the electrochemical behaviour of cobalt in aqueous H2CO3/HCO3–/CO32– solutions at pH 7–9

2004 ◽  
Vol 82 (5) ◽  
pp. 583-594 ◽  
Author(s):  
Stéphan Simard ◽  
Danick Gallant
Keyword(s):  
Open Circuit Potential ◽  
Competitive Adsorption ◽  
Carbonic Acid ◽  
Acid Corrosion ◽  
Electrochemical Behaviour ◽  
Open Circuit ◽  
Corrosion Process ◽  
Rotating Disc ◽  
Solution Interface ◽  
Potential Decay

The electrochemical behaviour of a cobalt rotating electrode in H2CO3/HCO3–/CO32– aqueous solutions was investigated in the pH region from 7 to 9. The effects of H2CO3/HCO3–/CO32– concentration, pH, and the presence of phosphates as inhibitors was explored using a rotating disc electrode at 1000 rpm. Some potentiodynamic experiments indicate that for pH 8.5 and higher, carbonate and bicarbonate species play a key role on the rate of electrooxidation of cobalt. For pH lower than 8.5, the electrochemical behaviour of cobalt changes drastically and very aggressive corrosion is observed. The involvement of carbonic acid must be considered in the corrosion process of cobalt in this pH region. The study of passive film potential decay under open circuit potential and galvanostatic reduction was performed on preanodized cobalt electrodes in solutions of various compositions. These experiments indicated the phenomena occurring at the electrode–solution interface during the corrosion process. A mechanism involving competitive adsorption of different species is suggested on the basis of the experimental evidence.Key words: cobalt, bicarbonate, phosphate, carbonic acid, corrosion.

UPD Zn2+ on low index single crystal platinum electrodes in acidic solutions

1994 ◽  
Vol 374 (1-2) ◽  
pp. 275-277 ◽  
Author(s):  
Satoshi Taguchi ◽  
Akiko Aramata ◽  
Md.A. Quaiyyum ◽  
Michio Enyo
Keyword(s):  
Single Crystal ◽  
Platinum Electrodes ◽  
Acidic Solutions

scholarly journals Caffeinated Interfaces Enhance Alkaline Hydrogen Electrocatalysis

2020 ◽  
Author(s):  
Saad Intikhab ◽  
Luis Rebollar ◽  
Yawei Li ◽  
Rahul Pai ◽  
Vibha Kalra ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Energy Storage ◽  
Hydrogen Oxidation ◽  
Molecular Engineering ◽  
Energy Storage And Conversion ◽  
Liquid Interfaces ◽  
Potential Cycling ◽  
Alkaline Fuel Cells ◽  
Pt Electrodes ◽  
Solid Liquid

<p>The high Pt loading required for hydrogen oxidation (HOR) and evolution (HER) reactions in alkaline fuel cells and electrolyzers adversely impacts the system cost. Here, we demonstrate the use of caffeine as a ‘double-layer dopant’ to enhance both the HER and HOR of Pt electrodes in base. HER/HOR rates increase by fivefold on Pt(111) and are accelerated on Pt(110), Pt(pc), and Pt/C as well. FTIR spectroscopy confirms that caffeine is adsorbed at the Pt surface, forming a self-limiting film through electrochemical deposition. Caffeine films are stable up to 1.0 V vs. RHE and are readily regenerated through caffeine deposition during load/potential cycling. The findings presented here both identify a potential catalyst additive that can mitigate high Pt loadings in alkaline fuel cells and electrolyzers while opening the door to molecular engineering of solid/liquid interfaces for energy storage and conversion.</p>

scholarly journals Electron transfer processes of coadsorbed Anthracene and N,N-Dimethylaniline on titania-silica

2004 ◽  
Vol 6 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Anna Eremenko ◽  
Natalie Smirnova ◽  
Oksana Yakimenko ◽  
Galina Starukh ◽  
David R. Worrall ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Competitive Adsorption ◽  
Co Adsorption ◽  
Decay Kinetics ◽  
Electron Transfer Process ◽  
Adsorption Sites ◽  
Transfer Processes ◽  
Pure Silica ◽  
Electron Transfer Processes ◽  
Kinetics Of

The effect of titania-silica binaries on the processes of PET and the decay kinetics of the Anthracene (An) fluorescence and An radical cation in presence of the co-adsorbed electron donor N,Ndimethylaniline (DMA) has been studied. The fluorescence of excited An adsorbed on pure silica is quenched by the addition of DMA, while co-adsorption of DMA on Ti/Si binaries resulted in increase of fluorescence intensity of adsorbed An. We suggest that competitive adsorption between DMA and An results in DMA occupying more active “titania” sites causing the shift of An molecules to weaker adsorption sites located on the silica support. An and DMA molecules being adsorbed simultaneously on the surface, effectively produce reduced titanium ions due to an electron transfer process. These data appear to lend weight to the suggestion of a pre-exciplex An-DMA state on the surface and effective PET from the excited molecular pair to the acceptor sites on the surface. These sites may be titania aggregates, or titania ions when there is a low content of Ti in the binaries.

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