Effect of dermasorbed oxygen on the catalytic activity of platinum indicator electrodes

Hoare, James P.

doi:10.1016/0013-4686(72)85083-7

Cited by 19 publications

(5 citation statements)

References 46 publications

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“…Our k eff 0 values were much higher than these literature values, most likely because very few of these studies used RDE to determine kinetic information, ,, and of those that did, our use of E onset instead of thermodynamic E 0 in the K-L equation (eq ) may have comparatively inflated k eff 0 . Our low values of α (about 0.2 to 0.3, Table ) do not require knowledge of E 0 and were more in line with literature reports of 0.12, 0.15, 0.21, 0.22, 0.31, and ∼0.4 at Pt; 0.33 and 0.35 at Au; 0.16 and 0.25 at GC; and 0.28 at carbon paste. Though Paulenova et al found Ce(SO 4 ) 2 to have 0.6 M solubility in 1 N H 2 SO 4 , Kaye and Laby report that CAN’s solubility is much higher, at 2.6 M, and this latter value was much more in agreement with what we observed experimentally (∼2.5 M in 1 M HNO 3 ).…”

Section: Resultssupporting

confidence: 92%

“…Our results suggest that employing an alternative cathode material may considerably improve the performance of such devices. VO 2 + ’s reduction has been tested at Pt , and Au previously, although using either of these catalysts is not straightforward. Although Pt has improved voltage and kinetics compared to GC, its waveform is just as complicated as GC’s, possibly showing multiple reductions of VO 2 + to VO 2+ and V 3+ (Figure ), or perhaps even an adsorptive process (i.e., a peak in the wave) that changes the activity of Pt midway through its reduction wave (Figure ).…”

Section: Resultsmentioning

confidence: 99%

“…The reduction of CAN involves just 1e − , but tetravalent cerium compounds are ferocious oxidizers, widely used in organic synthesis, with standard potentials estimated at +1.22 to +1.44 V in H 2 SO 4 and up to +1.7 V in HClO 4 . − Additionally, previous studies have indicated that Ce’s reduction occurs rapidly at Pt, ,,− Au, ,, and GC ,,,− electrodes, suggesting that CAN should serve as a high-voltage, high-performance fuel cell oxidant.…”

Section: Introductionmentioning

confidence: 99%

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Alternative Oxidants for High-Power Fuel Cells Studied by Rotating Disk Electrode (RDE) Voltammetry at Pt, Au, and Glassy Carbon Electrodes

et al. 2011

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Oxygen (O 2 ) reduction has long been the factor limiting the power density of most fuel cells. Membraneless, microfluidic fuel cells are a promising new fuel cell technology, yet they are affected even more strongly by O 2 , as they usually require a dissolved oxidant, and O 2 has minimal solubility in most solvents. Here we offer a detailed, analytical comparison of the performance of previously employed alternative oxidants, H 2 O 2 , MnO 4 -, VO 2 þ, and ClO -, at Pt, Au, and glassy carbon (GC) rotating disk electrodes (RDEs). We also investigated cerium ammonium nitrate (CAN), which has an exceptionally high potential for reduction. Of the oxidants studied, CAN offers the best immediate advantage, but MnO 4 -, though requiring development efforts, shows the most long-term promise for high-power fuel cells.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Alternative Oxidants for High-Power Fuel Cells Studied by Rotating Disk Electrode (RDE) Voltammetry at Pt, Au, and Glassy Carbon Electrodes

et al. 2011

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“…This higher activity on the alloy surface has been attributed to the presence of oxygen dissolved in the metal (13,14).…”

mentioning

confidence: 96%

“…For a given current density, the 02 overvoltage is reduced by 0.25-0.30V on a Pt-O alloy/Of electrode compared to a Pt/O2 electrode. This higher activity on the alloy surface has been attributed to the presence of oxygen dissolved in the metal (13,14).…”

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confidence: 99%

Some Aspects of the Reduction of Oxygen at a Platinum‐Oxygen Alloy Diaphragm

Hoare

1979

J. Electrochem. Soc.

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The steady-state galvanostatic polarization curve was obtained on the front side of a Pt aiaphragm in contact with O~-stirred 2N H2SO4 solution while the back side was in contact with concentrated HNOs. From low oxygen overvoltage (O2-~1) measurements it is shown that the rest potential is the reversible 02 l~otential. The rate of O2 reduction on the Pt-O alloy diaphragm is lower at high current densities than on a bright Pt cathode. At very high current densities the system is driven into the H2-evolution region where the H2-~ is close to the literature values for the Hf-TI on bright Pt. When the system was returned to open-circuit, the rest potential returned to the normal oxygen potential after about 24 hr. This time delay represents the time required to repair the complete layer of adsorbed oxygen atoms which had been removed by the strong cathodic current.

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Der Einfluß des Tunneleffektes auf die Geschwindigkeit von Redoxreaktionen an oxidbedeckten Platinelektroden

Kohl

Schultze

1973

Ber Bunsenges Phys Chem

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Edelmetallelektroden sind bei höheren Potentialen mit einer Oxidschicht bedeckt, die bei Redoxreaktionen den Elektronentransfer erschweren kann. Zur Untersuchung dieses Einflusses wurde die kathodische Reduktion von Cer‐(IV)‐lonen Ce4+ + e− ε Ce3+ an einer Platin‐Scheibenelektrode in Abhängigkeit vom Elektrodenpotential ε und von der mittleren Oxidschichtdicke dox im Bereich 5 Å < dox < 8 Å untersucht. Für die Durchtrittsstromdichte erhält man bei konstanter Schichtdicke angenähert eine Tafel‐Beziehung ε. Die Schichtdickenabhängigkeit bei konstantem Potential ε kann durch die Gleichung log i = A(e) ‐ doxdo beschrieben werden. die mit der bei zunehmender Schichtdicke dox abnehmenden Wahrscheinlichkeit für einen Tunnelübergang des Elektrons erklärt werden kann. Aus der Konstanten do kann die Höhe der Potentialschwelle abgeschätzt werden. Die Schichtdickenabhängigkeit anderer Redoxreaktionen, wie der kathodischen Chlorreduktion, der anodischen Sauerstoffentwicklung und der CO‐Oxydation, kann analog gedeutet werden.

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Effect of dermasorbed oxygen on the catalytic activity of platinum indicator electrodes

Cited by 19 publications

References 46 publications

Alternative Oxidants for High-Power Fuel Cells Studied by Rotating Disk Electrode (RDE) Voltammetry at Pt, Au, and Glassy Carbon Electrodes

Alternative Oxidants for High-Power Fuel Cells Studied by Rotating Disk Electrode (RDE) Voltammetry at Pt, Au, and Glassy Carbon Electrodes

Some Aspects of the Reduction of Oxygen at a Platinum‐Oxygen Alloy Diaphragm

Der Einfluß des Tunneleffektes auf die Geschwindigkeit von Redoxreaktionen an oxidbedeckten Platinelektroden

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