Limiting oxygen coverage on platinized platinum; Relevance to determination of real platinum area by hydrogen adsorption

Biegler, T.; Rand, D.A.J.; Woods, R.

doi:10.1016/s0022-0728(71)80089-x

Cited by 572 publications

(303 citation statements)

References 11 publications

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“…Firstly, in the special case of Pt electrode the EASA can be determined through the hydrogen adsorption from the electrolyte onto the Pt surface. The charge needed for underpotential deposition (UPD) of hydrogen (Q H ) can be obtained by integrating the surface area of hydrogen adsorption region in a cyclic voltammogram where the effect of the double layer capacitance has been subtracted [15]. For this method it is commonly assumed that the adsorption process of H UPD on Pt surface is a 1:1 (i.e.…”

Section: Electrochemically Active Surface Areamentioning

confidence: 99%

“…a hydrogen atom will adsorb on each Pt sites) [14] and that the charge required for adsorption on polycrystalline Pt to form a monolayer is Q H,mono = 210 µC cm 2 . This value is estimated with the assumption that the density of the atoms is 1.31 x 10 15 cm -2 [15,16] pertaining to the (100) face of the Pt electrode [17]. Overall, the electrochemical surface area can be determined with the equation…”

Section: Electrochemically Active Surface Areamentioning

confidence: 99%

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The correlation of electrochemical and fuel cell results for alcohol oxidation in acidic and alkaline media

Santasalo-Aarnio

Tuomi

Jalkanen

et al. 2013

Electrochimica Acta

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Section: Electrochemically Active Surface Areamentioning

confidence: 99%

Section: Electrochemically Active Surface Areamentioning

confidence: 99%

The correlation of electrochemical and fuel cell results for alcohol oxidation in acidic and alkaline media

Santasalo-Aarnio

Tuomi

Jalkanen

et al. 2013

Electrochimica Acta

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“…The charge involved in the H-UPD was converted to the real surface area using a conversion factor of 210 mC cm À2 [40,41]. The ratio between this surface and the geometric surface area of the electrode gave the roughness factor (RF).…”

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confidence: 99%

Bismuth‐Coated Mesoporous Platinum Microelectrodes as Sensors for Formic Acid Detection

2011

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Mesoporous platinum microeletrodes (MPtEs) modified by sub-monolayers of irreversibly adsorbed bismuth (BiMPtE) were investigated for their potential use as sensors for the detection of formic acid in direct formic acid fuel cells. The mesoporous platinum films were prepared by electrodeposition of platinum on Pt microdisks substrates 25 mm diameter, from hexachloroplatinic acid dissolved in the aqueous domain of the lyotropic liquid crystalline phase of octaethylene glycol monohexadecyl ether. The roughness factor (RF) of the MPtEs was about two orders of magnitude greater than those of the corresponding polished microelectrodes. Bismuth ad-atoms onto the platinum surface were deposited by under potential deposition from 1 mM Bi 3 + ions in 0.5 M H 2 SO 4 solutions. The catalytic activity of a series of Bi-MPtEs, characterized by different roughness and fractional bismuth coverage (q Bi ), towards the oxidation of HCOOH, was investigated by cyclic voltammetry and potential step experiments. Compared to MPtEs, Bi-MPtEs displayed enhanced electrooxidation currents at lower potentials. The stability of irreversibly adsorbed bismuth, and consequently the Bi-MPtEs catalytic activity, was found to depend on the high potential limit employed in the measurements. In general, both electrode stability and electrocatalytic performance were good, provided that the operational potential was kept 0.4 V vs. Ag/AgCl. Bi-MPtEs with q Bi > 0.3 provided almost sigmoidal shaped waves with low hysteresis, as those expected for microelectrodes working under steady state. The effect of concentration of HCOOH was investigated over the range 0.01-5 M, and linearity between current and concentration depended on both roughness factor and bismuth coverage. A Bi-MPtE characterised by RF = 210 and q Bi ! 0.6 provided linearity up to 2 M of formic acid. Reproducibility of the sensors was within 2 % (RSD). The same sensor, under the optimized experimental conditions, could be employed for at least two months with negligible loss of the initial performance.

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“…This charge density corresponds to the transfer of one electron to each one of the 1.3 x 10 15 atoms of Pt in 1 cm 2 of its surface. 37,38 In the present case, the calculated charge for desorbed H (dashed region in the voltammogram) was 66.60 μC and the corresponding active area was equal a 0.317 cm -2 . As the geometric area of the electrode was 0.181 cm 2 , the roughness factor for Pt was equal to 1.75.…”

mentioning

confidence: 50%

AFM studies and electrochemical characterization of boron-doped diamond surfaces modified with metal oxides by the Sol-Gel method

Suffredini¹,

Salazar‐Banda²,

Okamura³

et al. 2006

J. Braz. Chem. Soc.

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Com o objetivo de aprofundar investigações anteriores, foram realizadas modificações superficiais diretas em eletrodos de diamante dopados com boro (DDB), com óxidos metálicos (PtO x , RuO 2 , IrO 2 e PbO 2 ) e com alguns compósitos mistos, utilizando a técnica Sol-Gel. Estes materiais foram estudados por microscopia de força atômica (MFA) e os resultados indicaram a formação de sítios de deposição heterogênea. Técnicas eletroquímicas foram utilizadas para estabelecer a atividade catalítica para a reação de desprendimento de oxigênio (RDO) e para reação de oxidação de etanol em meio ácido utilizando os compósitos de PtO x e PtO x -RuO 2 . Testou-se ainda a estabilidade de um depósito de PtO x , recoberto por um filme de Nafion ® , por meio de operação contínua de longa duração. Estudos de voltametria cíclica comparativa mostraram que a área superficial ativa dos novos materiais mudou consideravelmente com o método de modificação proposto. O eletrodo de IrO 2 /BDD mostrou o melhor desempenho para a RDO, iniciando o processo de oxidação em ~ 1.4 V vs. HESS, valor este 200 mV menor do que o observado sobre um eletrodo de PtO x /BDD. Foi observada uma pequena perda da atividade do eletrodo de PtO x /BDD (6%) depois de realizada eletrólise de 4 horas, enquanto que 1000 ciclos voltamétricos deixaram a superfície praticamente inalterada. Os estudos realizados mostram que as atividades satisfatórias dos eletrodos preparados pelo método Sol-Gel podem constituir ferramentas interessantes de pesquisa, visando principalmente a utilização destes materiais em aplicações práticas.Continuing previous investigations, direct surface modifications of boron-doped diamond (BDD) electrodes with metal oxides (PtO x , RuO 2 , IrO 2 and PbO 2 ) and with some mixed composites were carried out by the Sol-Gel technique. The materials were studied by atomic force microscopy (AFM) to determine their surface topologies and by electrochemical techniques to establish the catalytic activity towards the oxygen evolution reaction (OER) and also, for the PtO x and PtO xRuO 2 composites, the ethanol oxidation reactions in acid media. The stability of PtO x coating covered by a Nafion ® film was also tested by long-term operation. The AFM results indicated sites of heterogeneous deposition and the electrochemical studies demonstrated that the active surface area changed considerably with the proposed method of modification. The IrO 2 /BDD electrode showed the best performance to the OER with the onset of the oxidation current at ~1.4 V, a value 200 mV lower than for the PtO x /BDD electrode. The enhanced stability of PtO x /BDD electrodes achieved by the application of a Nafion ® film and already reported in acid media was further proved using the ethanol oxidation reaction. Only a small loss of activity (6%) was observed after 4-hours electrolysis while one-thousand voltammetric cycles left the surface practically unchanged. In addition, preliminary studies for the same reaction on PtO x /BDD and PtO x -RuO 2 / BDD electrodes demonstrated the excell...

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Limiting oxygen coverage on platinized platinum; Relevance to determination of real platinum area by hydrogen adsorption

Cited by 572 publications

References 11 publications

The correlation of electrochemical and fuel cell results for alcohol oxidation in acidic and alkaline media

The correlation of electrochemical and fuel cell results for alcohol oxidation in acidic and alkaline media

Bismuth‐Coated Mesoporous Platinum Microelectrodes as Sensors for Formic Acid Detection

AFM studies and electrochemical characterization of boron-doped diamond surfaces modified with metal oxides by the Sol-Gel method

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