Electrooxidation of Hydroxyl Compounds Using Cerium Salts as Mediators: The Importance of Substrate Size for Catalyst Regeneration

Purgato, Fabiana L. S.; Romero, Juan

doi:10.1006/jcat.2002.3646

Cited by 5 publications

(11 citation statements)

References 49 publications

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“…All samples protected with the organic-inorganic hybrid coating showed EOC more positive than the bare substrate, indicating that the electrochemical response was modified. The sample doped with 500 ppm of Ce 4+ ions provided the noblest potential (0.4±0.1) V/(Ag/AgCl/KClsat) at initial immersion times, suggesting the formation of a denser cross linked coating, and the best protective character 13,16,21 . This EOC value also indicates that the barrier effect of the coating doped with 500 ppm of Ce 4+ ions induced a higher ohmic drop compared to the bare substrate and other coatings.…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…2B). The high frequency (HF) one is related to the organic-inorganic hybrid coating, and the other, in the low frequency (LF) domain, is attributed to the interfacial response (double layer charging in parallel with the charge transfer resistance) 16,22,26 . For the coatings doped with Ce 4+ ions ( Fig.…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…In previous works 10,21,22,28 , it has been reported that the addition of Ce 4+ ions to the hydrolysis solution provides an increase of the silanol groups condensation rate to form a denser and cross-linked coating. In addition, in organic chemistry, these ions are often used for the oxidation of alcohols [15][16][17][18]29,30 . The proposed general mechanism for such reaction shows that Ce 4+ ions form complexes with the ethanol molecules, which, when decomposed, form free radicals that react with each other leading to the polymerization of ethanol and / or silanol by a polymerization redox reaction 16,19 .…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…In addition, in organic chemistry, these ions are often used for the oxidation of alcohols [15][16][17][18]29,30 . The proposed general mechanism for such reaction shows that Ce 4+ ions form complexes with the ethanol molecules, which, when decomposed, form free radicals that react with each other leading to the polymerization of ethanol and / or silanol by a polymerization redox reaction 16,19 . This redox polymerization process is characteristic of ethanol in the presence of Ce 4+ ions.…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…The use of ceric sulfate, in the modification of polymers and organic-inorganic hybrid materials by redox polymerization reaction is a widely used method with industrial importance [11][12][13][14][15][16] . For organic-inorganic hybrid materials, it is proposed that silanol molecules (R1-Si-(OH)3) and alcohol from the hydrolyzed precursors can complex with Ce 4+ ions to produce free radicals, thus increasing the polymerization and the polycondensation degree of the siloxane (Si-O-Si) network [17][18][19][20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

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Influence of Ce(IV) ions amount on the electrochemical behavior of hybrid films in 0.1 mol L-1 NaCl solution

et al. 2019

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In this work, the influence of ceric ions (Ce(SO4)2) addition to the hydrolysis solution on the corrosion protection afforded by organic-inorganic hybrid coating obtained from tetraethoxysilane (TEOS) and 3-methacryloxy-propyl-trimethoxysilane (MPTS) to a carbon steel substrate in 0.1 mol L-1 NaCl solution was studied. Open circuit potential (EOC) and electrochemical impedance spectroscopy (EIS) experiments were carried out and showed that the protection afforded by the organic-inorganic hybrid coating was extremely dependent on the Ce4+ ions amount. These results were in close agreement with optical microscopy observation of the degrading surfaces, both procedures showing that more protective coating was produced when 500 ppm of Ce4+ ions were added to the organic-inorganic hybrid solution. The chemical state of the organic-inorganic hybrid coating investigated by X-ray photoelectron spectroscopy (XPS) indicated that the addition of Ce4+ ions enhances the polycondensation degree of the organic-inorganic hybrid coating leading to a denser siloxane (Si-O-Si) network. A strategy using laser-induced breakdown spectroscopy (LIBS) and UV-Vis spectrometry was set up in order to verify, respectively, the presence of Ce ions within the coating structure and its oxidation state. LIBS results confirmed the incorporation of Ce ions in the coating, which, according to UV-Vis measurements, are mainly in the (IV)-oxidation state.

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Section: Electrochemical Measurementsmentioning

confidence: 99%

Section: Electrochemical Measurementsmentioning

confidence: 99%

Section: Electrochemical Measurementsmentioning

confidence: 99%

Section: Electrochemical Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of Ce(IV) ions amount on the electrochemical behavior of hybrid films in 0.1 mol L-1 NaCl solution

et al. 2019

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Influence of cerium (IV) ions on the mechanism of organosilane polymerization and on the improvement of its barrier properties

Suegama

Melo

Benedetti

et al. 2009

Electrochimica Acta

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Effect of cerium concentration on corrosion resistance and polymerization of hybrid sol–gel coating on martensitic stainless steel

Cambon

Ansart

Bonino

et al. 2012

Progress in Organic Coatings

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Stainless steels are increasingly used in the aeronautics field for the manufacture of structural parts. One of them, the X13VD martensitic stainless steel (X12CrNiMoV12-3), known for its good mechanical properties, has a poor corrosion resistance in confined or severe environments. In the past years, Cr(VI) based pre-treatments have been currently used for corrosion protection of different metals, however, they are toxic and due to environmental regulations, they will be definitely banned in a near future. Alternatives to replace Cr(VI) show advantages and drawbacks considering key properties such as: corrosion resistance, adhesion of coatings, fatigue resistance, durability and reliability. However, some of their possible alternatives show high potential. In this paper, a process was developed to improve the corrosion resistance of the martensitic stainless steel. Organic-inorganic hybrid coatings with different cerium concentrations were deposited onto stainless steel by sol-gel process. Corrosion resistance of the coatings was evaluated by electrochemical impedance measurements and it has been proved that cerium concentration of 0.01 M into hybrid coating was an optimal content. Adhesion tests were also carried out by "nanoscratchtest" to characterize the coatings mechanical properties as a function of cerium concentration but results do not clearly show the influence of cerium for the coating adhesion toward the substrate. To try to correlate with the electrochemical properties, liquid 29 Si NMR spectroscopy was then performed to investigate hydrolysis and condensation reactions of sol-gel process, and by this method, it was demonstrated that for higher cerium concentration (>0.01 M) there is a modification of the chemical structure of the sol-gel network.

show abstract

Electrooxidation of Hydroxyl Compounds Using Cerium Salts as Mediators: The Importance of Substrate Size for Catalyst Regeneration

Cited by 5 publications

References 49 publications

Influence of Ce(IV) ions amount on the electrochemical behavior of hybrid films in 0.1 mol L-1 NaCl solution

Influence of Ce(IV) ions amount on the electrochemical behavior of hybrid films in 0.1 mol L-1 NaCl solution

Influence of cerium (IV) ions on the mechanism of organosilane polymerization and on the improvement of its barrier properties

Effect of cerium concentration on corrosion resistance and polymerization of hybrid sol–gel coating on martensitic stainless steel

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