Electroreduction of Dioxygen on Polycrystalline Platinum in Alkaline Solution I. Platinum Surface Pretreated by Potential Cycling Between 40 and 1450 mV

2000 ◽  
Vol 147 (9) ◽  
pp. 3436 ◽  
Author(s):  
Carlos Paliteiro ◽  
Lucı́lia Batista
Keyword(s):  
Alkaline Solution ◽  
Potential Cycling ◽  
Platinum Surface ◽  
Polycrystalline Platinum

The Adsorption, Desorption, and Exchange Reactions of Oxygen, Hydrogen, and Water on Platinum Surfaces. II. Hydrogen Adsorption, Exchange, and Equilibration

1975 ◽  
Vol 53 (2) ◽  
pp. 298-306 ◽  
Author(s):  
Y. K. Peng ◽  
P. T. Dawson
Keyword(s):  
Hydrogen Adsorption ◽  
Surface Composition ◽  
Co Adsorption ◽  
Exchange Reactions ◽  
Platinum Surface ◽  
Polycrystalline Platinum ◽  
Platinum Surfaces ◽  
Exponential Factors ◽  
Apparent Activation Energies ◽  
Adsorption Desorption

The adsorption, desorption, exchange, and equilibration reactions of hydrogen and deuterium on a platinum filament have been investigated by thermal desorption mass spectrometry. A surface saturated with hydrogen at 120 °K has a coverage 4.2 × 1014 molecules cm−2 and gives desorption spectra with four distinct peaks: β1,(165 °K), β2(220 °K), β3(280 °K), and β4(350 °K). Apparent activation energies and pre-exponential factors were determined for the β2-, β3-, and β4-peaks. For both co-adsorption and sequential adsorption of H2 and D2 the mass 2, 3, and 4 desorption spectra have identical shapes and the gas desorbs at equilibrium throughout. It is concluded that hydrogen adsorbs dissociatively. Exchange and equilibration were studied at 120, 210, and 285 °K by determining the surface composition and isotope distribution after varying fractions of preadsorbed H had been replaced. Following exchange at 120 °K the desorption spectra show a higher D content and a lack of equilibrium in the desorbing gas at low temperature. In most other experiments the mass 2,3, and 4 desorption spectra had identical shapes and the gas desorbed at equilibrium. The results are interpreted by a model which requires that the polycrystalline platinum surface is intrinsically heterogeneous. It appears that different mechanisms are unnecessary to interpret the differences in kinetics observed for exchange and equilibration at low temperatures.

Temperature effect on the removal of hydroxyl radicals by a polycrystalline platinum surface

1983 ◽  
Vol 87 (11) ◽  
pp. 1906-1910 ◽  
Author(s):  
G. T. Fujimoto ◽  
G. S. Selwyn ◽  
J. T. Keiser ◽  
M. C. Lin
Keyword(s):  
Temperature Effect ◽  
Hydroxyl Radicals ◽  
Platinum Surface ◽  
Polycrystalline Platinum

scholarly journals Influence of Chemical Operation on the Electrocatalytic Activity of Ba0.5Sr0.5Co0.8Fe0.2O3−δ for the Oxygen Evolution Reaction

2021 ◽  
Author(s):  
Yuta Inoue ◽  
Yuto Miyahara ◽  
Kohei Miyazaki ◽  
Yasuyuki Kondo ◽  
Yuko Yokoyama ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Alkaline Solution ◽  
Oxygen Evolution Reaction ◽  
Time Course ◽  
Potential Cycling ◽  
Leaching Behavior ◽  
Fundamental Understanding ◽  
A Site

Abstract Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) is a promising electrocatalyst for the oxygen evolution reaction (OER) in alkaline solution. The OER activities of BSCF are gradually enhanced by prolonging the duration of electrochemical operation at OER potentials, but the underlying cause is not fully understood. In this study, we investigated the role of chemical operation, equivalent to immersion in alkaline solution, in the time-course of OER enhancement of BSCF. Interestingly, the time-course OER enhancement of BSCF was promoted not only by electrochemical operation, which corresponds to potential cycling in the OER region, but also by chemical operation. In situ Raman measurements clarified that chemical operation had a lower rate of surface amorphization than electrochemical operation. On the other hand, the leaching behavior of A-site cations was comparable between chemical and electrochemical operations. Since the OER activity of BSCF was stabilized by saturating the electrolyte with Ba2+, “chemical” A-site leaching was key to inducing the time-course OER enhancement on perovskite electrocatalysts. Based on these results, we provide a fundamental understanding of the role of chemical operation in the OER properties of perovskites.

Lead deposition onto a polycrystalline platinum surface

1981 ◽  
Vol 105 (1) ◽  
pp. A129 ◽  
Author(s):  
G. Praline ◽  
N. Pacia ◽  
J.J. Ehrhardt ◽  
A. Cassuto ◽  
J.P. Langeron
Keyword(s):  
Platinum Surface ◽  
Polycrystalline Platinum
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