XPS study of the state of iridium, platinum, titanium and oxygen in thermally formed IrO2+TiO2+PtOX films

Silva, Luís Antônio da; Alves, Valéria Almeida; Castro, Stella; Boodts, Julien Françoise Coleta

doi:10.1016/s0927-7757(99)00535-x

Cited by 86 publications

(48 citation statements)

References 27 publications

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“…(62.3-62.8 eV) to Ir(IV). Consistently with this interpretation Da Silva et al [17] report a majority presence of the Ir(III) oxide component for a commercial IrO 2 sample while in the case of ternary IrO 2 + TiO 2 + PtO x composites observe only the occurrence of the Ir(IV), its surface concentration decreasing with the progressive Pt addition. Other authors, instead, attribute the same doublets respectively to Ir(IV) and to Ir in a higher oxidation state [30,31].…”

Section: Xps Analysessupporting

confidence: 56%

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Composite ternary SnO2–IrO2–Ta2O5 oxide electrocatalysts

Ardizzone

Bianchi

Cappelletti

et al. 2006

Journal of Electroanalytical Chemistry

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Section: Xps Analysessupporting

confidence: 56%

“…There is considerable disagreement in the literature about the nature of the components of the Ir 4f 7/2 peak in the case of IrO 2 . Several authors [17,29] attribute the main component to Ir(III) (61.6-62.0 eV), and the second component at higher B.E. (62.3-62.8 eV) to Ir(IV).…”

Section: Xps Analysesmentioning

confidence: 99%

Composite ternary SnO2–IrO2–Ta2O5 oxide electrocatalysts

Ardizzone

Bianchi

Cappelletti

et al. 2006

Journal of Electroanalytical Chemistry

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“…However, new composite materials, based on IrO 2 dispersed in a less costly metal oxide as matrix, can lead to the development of new electrodes with good chemical resistance to the acidic environment and good electronic conductivity [17,21]. A large number of oxidic systems have been obtained by changing the dispersing agent, the metal, the synthetic procedure and the mass ratio between components [17,[21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

New electrocatalytic materials based on mixed metal oxides: electrochemical quartz crystal microbalance characterization

et al. 2008

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An electrochemical Quartz Crystal Microbalance (EQCM) was used to characterize a mixed metal oxide electrocatalyst, Ir 0.15 Sn 0.85 O 2 , for the Oxygen Evolution Reaction (OER) in acidic medium in the potential range of the pseudo-capacitance reaction, from 0.4 to 1.2 V versus Reversible Hydrogen Electrode (RHE). The EQCM gold tip was characterized in H 2 SO 4 0.05 M and HClO 4 0.1 M. Subsequently, Ir 0.15 Sn 0.85 O 2 powder, synthesized by a solgel route, was supported on the tip gold surface for investigations in the same media. The simultaneous measurements of mass variation and current density as functions of potential led to the identification of the chemical species involved in the mass transfer between the oxide and the acidic solution during the pseudo-capacitance reaction.

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“…As for pH sensing, iridium oxide electrodes have the advantage that they can be used in aggressive media, at high temperatures [16] and also in non-aqueous solutions [17]. Methods proposed for fabrication of iridium oxide films include electrochemical growth [2,11,18] anodic electrodeposition [10,12,19,20], thermal salt decomposition [1,2,21,22], reactive sputtering [23,24], melt oxidation [15], sol-gel method [9,22,25]. Substrates used for deposition of iridium oxide layers are also numerous.…”

Section: Introductionmentioning

confidence: 99%

Iridium Anodic Oxidation to Ir(III) and Ir(IV) Hydrous Oxides

et al. 2005

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Iridium oxide films (IROFs) are known to have an enhanced or the so-called super-Nernstian (< 59 mV/pH) pHsensitivity. The intention in the present study was to find out the reasons of such behavior and also to elucidate the nature of iridium anodic oxidation processes. The methods employed were combined cyclic voltammetry and chronopotentiometry. Iridium layers of 0.1 to 0.2 mm thickness, deposited thermally on titanium or gold-plated titanium substrates, were used for investigations. IROFs on the surface of working electrodes were formed anodically by applying a constant potential in deaerated and oxygen-containing solutions of 0.5 M H 2 SO 4 , 0.1 M KOH and 0.5 M H 3 PO 4 þ KOH. Linear pH-dependences of the stationary open-circuit potential with the slopes close to 59 mV/pH were found for iridium electrode oxidized at 0.4 V -0.8 V (RHE) in deaerated and at 0.8 V -1.2 V (RHE) in O 2 -containing solutions. They were attributed to reversible Ir/Ir(OH) 3 and Ir/ IrO 2 · nH 2 O metal-oxide electrodes, respectively. It has been suggested that the main current peaks seen in the voltammograms of iridium electrode in acid and alkaline solutions are of different nature. The difference between iridium electrode surface states in acid and alkaline solutions has been presumed to be the main reason of super-Nernstian pH-sensitivity of the IROFs. On the basis of the results obtained standard potential of Ir/Ir(OH) 3 electrode and the solubility product of Ir(OH) 3 have been evaluated: E Ir=IrðOHÞ 3 ¼ 0.78 AE 0.02 V and K sp ¼ 3.3 Â 10 À64 .

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XPS study of the state of iridium, platinum, titanium and oxygen in thermally formed IrO2+TiO2+PtOX films

Cited by 86 publications

References 27 publications

Composite ternary SnO2–IrO2–Ta2O5 oxide electrocatalysts

Composite ternary SnO2–IrO2–Ta2O5 oxide electrocatalysts

New electrocatalytic materials based on mixed metal oxides: electrochemical quartz crystal microbalance characterization

Iridium Anodic Oxidation to Ir(III) and Ir(IV) Hydrous Oxides

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