Influence of the electrode history and effects of the electrolyte composition and temperature on O2 evolution at β-PbO2 anodes in acid media

Амаделли, Р.; Maldotti, Andrea; Molinari, Alessandra; Данилов, Ф. И.; Величенко, А. Б.

doi:10.1016/s0022-0728(02)01152-x

Cited by 119 publications

(69 citation statements)

References 46 publications

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“…We later confirmed that the presence of a hydrous layer has an important role in the mechanism of anodic reactions on PbO 2 [7]. The oxidation of H 2 O (reaction 3) is seemingly favoured when it occurs in the gel layer rather than on a crystalline surface, in accordance with literature reporting that interaction of water with defective oxide surfaces is stronger in comparison with regular ones [8].…”

Section: Introductionsupporting

confidence: 89%

Electrode characteristics for ozone production: a case study using undoped and doped PbO2 on porous platinised titanium substrates

Rosestolato

Амаделли

Величенко

2015

J Solid State Electrochem

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The primary aim of this paper is the study of the stability and electrochemical activity of PbO 2 electrodeposited onto porous, platinised Ti substrates. The evolution of O 2 from H 2 O oxidation, on as-prepared electrodes, results in the opening of large pores that effectively work as gas channels for removing O 2 generated inside the porous structure, thus favouring the reaction penetration deeper into the pores. A serious problem that limits the utilisation of the internal pore surface is the instability of PbO 2 towards corrosion at high positive potentials or currents. Occlusion of pores by corrosion products is clearly demonstrated by SEM analysis of electrodes after operation as O 2 evolving anodes. Doping PbO 2 with Fe 3+ and Co 2+ yields anodes that resist corrosion up to relatively high anodic potentials/currents; this extends the anode lifetime by decreasing amorphisation of the electrocatalyst and its partial detachment caused by a high pressure of O 2 formed inside the pores during water electrolysis. This is an important result since stability of electrodes is as important as their electrochemical activity for practical applications.In the domain of high positive potentials, PbO 2 doping by Fe 3+ and Co 2+ results in a significant increase of the current efficiency of ozone generation. The magnitude of the observed increase depends on the individual characteristics of the doping cation and of the electrolyte employed. Possible involvement of higher oxidation states of cobalt and iron in the reaction mechanism is discussed on the basis of published literature.

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Section: Introductionsupporting

confidence: 89%

Electrode characteristics for ozone production: a case study using undoped and doped PbO2 on porous platinised titanium substrates

Rosestolato

Амаделли

Величенко

2015

J Solid State Electrochem

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“…Even though in some of these applications the use of non-noble metal-based electrodes such as PbO 2 can be justified [2,3], all of them would benefit from the development of a more active alternative. Electrode stability, however, should not be sacrificed.…”

Section: Introductionmentioning

confidence: 99%

Using Instability of a Non-stoichiometric Mixed Oxide Oxygen Evolution Catalyst As a Tool to Improve Its Electrocatalytic Performance

et al. 2017

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Owing to their superior electrocatalytic performance, non-stoichiometric mixed oxides are often considered as promising electrocatalysts for the acidic oxygen evolution reaction (OER). Their activity and stability can be superior to those of the state-of-the-art IrO 2 catalysts, although the exact nature of this phenomenon is not yet understood. In the current work, a Ir 0.7 Sn 0.3 O 2-x thin-film electrode is taken as a representative example for a thorough evaluation of OER activity of the non-stoichiometric oxides. Complementary activity and stability analysis of Ir 0.7 Sn 0.3 O 2-x electrodes is achieved using a setup based on an electrochemical scanning flow cell and ICP-MS. The obtained ICP-MS data presents an unambiguous proof of the preferential dissolution of the less noble Sn from the mixed oxide during OER. While less than a monolayer of Ir is dissolved after a prolonged electrolysis of 1400 min during which its dissolution rate drops to near zero, the amount of Sn lost is ten monolayers. The latter finding is confirmed by XPS analysis, which besides showing Ir surface enrichment also indicates a gradual transformation of Ir 0 to Ir III species. This transition is beneficial for electrode activity, as the overpotential for OER at j = 5 mA cm −2 was decreasing up to 300 mV. The increase in electrode activity is attributed to several mechanisms including generation of Ir III active sites and overall surface area increase. A generalized description of OER catalysis by Ir-based materials is given, including data from the current work as well as from other Ir-based mixed oxides, such as Ir-Ru-O and Ir-Ni-O.

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“…Titanium substrates covered with platinum (Ti-Pt) are well known to lead to good stability of the PbO 2 films, 12 with low levels of Pb 2+ ions released into solution; 28 however the extensive use of platinum is not economically feasible. Thus, many PbO 2 anodes prepared directly on the Ti substrate have been reported, with previous substrate pretreatment or modification: sandblasting followed by etching in concentrated hydrochloric acid; 29 polishing with 320-grit paper strips, etching in boiling 20% hydrochloric acid for 1 h followed by deposition of a SnO 2 -Sb coating; 30 and etching in boiling 1.6 mol L -1 oxalic acid for 2 h. 27 The presence of fluorine ions 31 or surfactants 32 in the electrodeposition bath can contribute to a more stable oxide film due to the diminishment of the amount of oxygen evolution, which could cause cracks in the oxide surface leading to scaling. Furthermore, these species can improve the PbO 2 film adherence 21 and its crystallinity.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, these species can improve the PbO 2 film adherence 21 and its crystallinity. 31 Studies on the degradation of the diazo dye Direct Yellow 86 -DY 86 (CAS number 50925-42-3 and C.I. number 29325 - Figure 1) 34 reported on its decolorization by Aeromonas hydrophila, comparatively to other dyes in order to study the effect of chemical structure.…”

Section: Introductionmentioning

confidence: 99%

A comparison of electrodeposited Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes in the electrochemical degradation of the direct yellow 86 dye

Aquino¹,

Irikura²,

Rocha‐Filho³

et al. 2010

Quím. Nova

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The electrochemical performance of electrodeposited Ti/β-PbO 2 and Ti-Pt/β-PbO 2 anodes was galvanostatically evaluated (batch mode, 50 mA cm -2 ) to degrade the Direct Yellow 86 dye (100 or 200 mg L -1 in 0.1 mol L -1 Na 2 SO 4 + 1.5 g L -1 NaCl), investigating the effect of pH and temperature. Similar results were obtained for both electrodes and the best conditions for removal of color and chemical oxygen demand are pH 7 and 40 °C, when 90% decolorization is attained by passing a charge of only ~0.13 A h L -1 and total mineralization is achieved with expenditure of ~5 kW h m -3 .

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Influence of the electrode history and effects of the electrolyte composition and temperature on O2 evolution at β-PbO2 anodes in acid media

Cited by 119 publications

References 46 publications

Electrode characteristics for ozone production: a case study using undoped and doped PbO2 on porous platinised titanium substrates

Electrode characteristics for ozone production: a case study using undoped and doped PbO2 on porous platinised titanium substrates

Using Instability of a Non-stoichiometric Mixed Oxide Oxygen Evolution Catalyst As a Tool to Improve Its Electrocatalytic Performance

A comparison of electrodeposited Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes in the electrochemical degradation of the direct yellow 86 dye

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