Potential dependence of methanol electrosorption on platinum

1969 ◽  
Vol 22 (8) ◽  
pp. 1583 ◽  
Author(s):  
T Biegler
Keyword(s):  
Steady State ◽  
Acid Solution ◽  
Adsorption Equilibrium ◽  
Platinum Electrode ◽  
Reversible Hydrogen Electrode ◽  
Trace Impurities ◽  
Hydrogen Electrode ◽  
Potential Dependence ◽  
Irreversible Oxidation ◽  
Steady Stage

Adsorption of methanol from acid solution onto a smooth platinum electrode is studied using fast anodic potential sweeps to determine coverages. Between 0.15 and 0.6 V (against reversible hydrogen electrode) the coverage is found to be almost independent of potential. Below 0.15 V coverage measurements are unreliable because of the very slow approach to the steady state and competition for the surface by trace impurities. The results are consistent with the hypothesis that chemisorbed methanol is a stable intermediate in a sequence of irreversible oxidation stages and that the steady-stage coverage cannot be considered as a true adsorption equilibrium.

scholarly journals Copper Metallopolymer Catalyst for the Electrocatalytic Hydrogen Evolution Reaction (HER)

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 110 ◽  
Author(s):  
Sait Elmas ◽  
Thomas Macdonald ◽  
William Skinner ◽  
Mats Andersson ◽  
Thomas Nann
Keyword(s):  
Conjugated Polymers ◽  
Conjugated Polymer ◽  
Electrode Materials ◽  
Hydrogen Generation ◽  
Platinum Electrode ◽  
Metal Electrode ◽  
Reversible Hydrogen Electrode ◽  
Hydrogen Electrode ◽  
Highly Active ◽  
P Type

Conjugated polymers with stabilizing coordination units for single-site catalytic centers are excellent candidates to minimize the use of expensive noble metal electrode materials. In this study, conjugated metallopolymer, POS[Cu], was synthesized and fully characterized by means of spectroscopical, electrochemical, and photophysical methods. The copper metallopolymer was found to be highly active for the electrocatalytic hydrogen generation (HER) in an aqueous solution at pH 7.4 and overpotentials at 300 mV vs. reversible hydrogen electrode (RHE). Compared to the platinum electrode, the obtained overpotential is only 100 mV higher. The photoelectrochemical tests revealed that the complexation of the conjugated polymer POS turned its intrinsically electron-accepting (p-type) properties into an electron-donor (n-type) with photocurrent responses ten times higher than the organic photoelectrode.

Effects of the Substitution of Β-Site Ion on Oxygen Reduction Electrode Properties of Pb2Ru2O7- δ in Aqueous Solutions

2007 ◽  
Vol 350 ◽  
pp. 171-174 ◽  
Author(s):  
Kenji Yoshihara ◽  
Yoshinobu Saito ◽  
Morihiro Saito ◽  
Jun Kuwano ◽  
Hidenobu Shiroishi
Keyword(s):  
Steady State ◽  
Aqueous Solutions ◽  
Oxygen Reduction ◽  
Lattice Parameter ◽  
Reversible Hydrogen Electrode ◽  
Hydrogen Electrode ◽  
Onset Voltage ◽  
Electron Reduction ◽  
Disk Electrodes ◽  
Electrochemical Oxygen

The activities of the pyrochlores Pb2Ru2-xMxO7-δ (M=Mn,Fe,Co,Ni)[PRM(0x)] toward electrochemical oxygen reduction (EOR) were examined in 0.1 M KOH and 0.05 M H2SO4 aqueous solutions. The onset voltage (Vo) and the efficiency (E4) of 4-electron reduction of oxygen for PRM(0x) were evaluated by semi-steady state voltammetry with rotating ring-disk electrodes. In PRM01, the order of the EOR activities was PRMn01 > PRCo01 > PRNi01 > PRFe01 in both solutions. This was consistent with the variation of the lattice parameters, i.e. PRM01 with a smaller lattice parameter showed higher EOR activity. In addition, PRMn05 showed higher EOR activity than PRMn01. The onset voltages Vo were 0.95 and 0.50 V vs. reversible hydrogen electrode in 0.1 M KOH and 0.05 M H2SO4, respectively, while E4 was almost 100 % in both solutions. These results indicate that the EOR activity of PRM(0x) depends on the incorporated metal ions on the B-sites and their contents.

Adsorption and Oxidation of Thiosulfate on the Platinum Electrode in a Slightly Alkaline Medium

2000 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Adsorbed Layer ◽  
Open Circuit ◽  
Adsorbed Hydrogen ◽  
Oxidation Number ◽  
Hydrogen Electrode ◽  
Layer Region

The aim of this research was to study the oxidation and reduction of the adsorbed thiosulfate on the platinum electrode in a slightly alkaline medium. The adsorption was performed at the open circuit conditions. The reduction of the adsorbed layer in the hydrogen region is slower in a slightly alkaline medium than in acid. The mechanism of reduction and oxidation of adsorbed molecules is probably the same. The nonstationary currents measured in presence of thiosulfates showed that the change in the oxidation number does not take place during the adsorption in the double layer region. In the hydrogen region, thiosulfate replaces the adsorbed hydrogen while beeing reduced. Nonstationary currents at higher concentrations of thiosulfate indicate the presence of more layers on the electrode. Upon reaching higher concentrations of thiosulfate the oxidation reaction takes place between thiosulfate in solution and adsorbed product of its reduction. The open circuit potential of the platinum electrode measured in a thiosulfate solution was 0.780 and 0.783 V against the hydrogen electrode in the same solution.

scholarly journals The amount of hydrogen and oxygen present on the surface of a metallic electrode

1929 ◽  
Vol 125 (798) ◽  
pp. 446-462 ◽  
Keyword(s):  
Linear Function ◽  
Linear Relation ◽  
Electrode Potential ◽  
Reversible Hydrogen Electrode ◽  
Acid Electrolyte ◽  
Hydrogen Electrode ◽  
Metallic Electrode ◽  
Mercury Surface ◽  
First Approximation ◽  
Accessible Area

In a pervious communication a study has been made of the potential changes which occur during the discharge of small quantities of electricity at metallic cathodes in an acid electrolyte. The electrode potential was, in general, more negative than the reversible hydrogen electrode, and it was found that over this range the potential change was a linear function of the quantity of electricity passed. This quantity was very small, 6 X 10 -7 coulombs per square centimetre causing a change of 100 millivolts in the electrode potential at a mercury surface. This linear relation was found on all the metals investigated, but the quantity varied with the nature and condition of the surface, being greater the rougher the surface. Experiments with amalgams, and platinised mercury surfaces showed that this quantity was, to a first approximation, accessible area of its surface. It was suggested that this change in potential may be regarded as due to the deposition of more hydrogen dipoles to the surface, or alternatively to a flux of electricity across the interface causing a further deformation of the hydrogen dipoles already present on the surface. Although the potential changes accompanying these additions to the surface have been studied, few measurements were made of the quantity of hydrogen initially present on the surface at the reversible hydrogen potential. It was considered probable that this was approximately a monatomic layer but it was of some interest to investigate this point.

scholarly journals The Synthesis of V2O3 Nanorings by Hydrothermal Process as an Efficient Electrocatalyst Toward N2 Fixation to NH3

2020 ◽  
Vol 8 ◽  
Author(s):  
Ning Wang ◽  
Qing-Song Song ◽  
Wen-Jing Liu ◽  
Jian Zhang
Keyword(s):  
Noble Metal ◽  
Hydrothermal Process ◽  
Maximum Yield ◽  
Reduction Reaction ◽  
Reversible Hydrogen Electrode ◽  
Proof Of Concept ◽  
Ambient Conditions ◽  
Hydrogen Electrode ◽  
Etching Mechanism ◽  
Template Free

A new ringlike V2O3 architecture was successfully synthesized by a template-free hydrothermal method, and the sulfur ions-assisted central-etching mechanism of the ringlike structure was proposed. Herein, as a proof-of-concept experiment, taking V2O3 nanorings as non-noble-metal-free nitrogen reduction reaction (NRR) catalysts, they show desired electrocatalytic performance toward NRR under ambient conditions (maximum yield: 47.2 µg h−1 mgcat.−1 at −0.6 V vs. reversible hydrogen electrode, maximum Faraday efficiency: 12.5% at −0.5 V vs. reversible hydrogen electrode), which is significantly higher than those of noble metal-based catalysts.

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