Pourbaix Diagrams for Multielement Systems

Thompson, W. T.; Kaye, M.H.; Bale, C. W.; Pelton, Arthur D.

doi:10.1002/9780470872864.ch8

Cited by 36 publications

(37 citation statements)

References 1 publication

(1 reference statement)

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“…The absence of Ag(I) and TiOH electrostatic repulsion gives an increase in the photoreduction conversion. Based on the Pourbaix diagram 19 , at pH 6 silver oxide compound has not been formed, so the UV light is not blocked and easily to reach the TiO 2 surface, leading to better photoreduction reaction.…”

Section: Resultsmentioning

confidence: 99%

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Fe3O4/SiO2/TiO2 Core-Shell Nanoparticles as Catalyst for Ag(I) Ions

Kunarti¹,

Roto²,

Pradipta³

et al. 2017

Orient. J. Chem

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Nanosized-photocatalysts with additional magnetic functionality have been studied extensively for many potential applications. Fe 3 O 4 /SiO 2 /TiO 2 core-shell nanoparticles have been evaluated as catalyst for photoreduction of aqueous solution of Ag(I) ions. The nanoparticles was prepared by coating Fe 3 O 4 with SiO 2 and TiO 2 consecutively through sol-gel process followed by microwaveassisted treatment. The prepared nanoparticles were confirmed by XRD and TEM. A photocatalytic reaction was carried out in a batch system with a UV-irradiation wavelength of 340-390 nm. The effects of catalyst loading, irradiation time and solution pH were studied. The Ag(I) photoreduction progress was monitored by AAS. The obtained Fe 3 O 4 /SiO 2 /TiO 2 core-shell nanoparticles can reduce 97% of Ag(I) in the solution whereas unmodified TiO 2 solids can only reduce 37% of the ion. The photocatalytic reaction could be best performed at pH 6, irradiation time of 2 h, and initial Ag(I) concentration of 25 mg/L. The prepared materials could be of interests in the treatment of waste containing toxic heavy metal ions.

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Section: Resultsmentioning

confidence: 99%

“…After absorbing UV light with appropriate energy, the 19 . The presence of these silver oxides caused the increase of solution turbidity.…”

Section: Resultsmentioning

confidence: 99%

Fe3O4/SiO2/TiO2 Core-Shell Nanoparticles as Catalyst for Ag(I) Ions

Kunarti¹,

Roto²,

Pradipta³

et al. 2017

Orient. J. Chem

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“…Then, in analogy to rechargeable batteries, Ni II (pale green Ni(OH) 2 ) may be oxidized to Ni III (black NiOOH). 48,49 Since NiOOH is a good mixed-conductor, with a high mobility of ionic and electronic species, its presence does not much impede the electrochemical performance of capacitors utilizing nickel collectors.…”

Section: Improvement Of Long Time Performance By Coupling Of Differenmentioning

confidence: 99%

Strategies to Improve the Performance of Carbon/Carbon Capacitors in Salt Aqueous Electrolytes

Abbas

Ratajczak

Babuchowska

et al. 2015

J. Electrochem. Soc.

107

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Strategies are presented to enhance operating potential and cycle life of AC/AC capacitors using salt aqueous electrolytes. Li 2 SO 4 (pH = 6.5) allows 99% efficiency to be exhibited at 1.6 V cell potential with low self-discharge, while in BeSO 4 (pH = 2.1) efficiency is low (81%). Li 2 SO 4 performs better due to high di-hydrogen over-potential at the negative electrode and related pH increase in AC porosity. When stainless steel current collectors are used in Li 2 SO 4 , the cell resistance suddenly increases after 12 hours floating at 1.6 V, due to corrosion of the positive collector. With nickel negative and stainless steel positive collectors, the electrode potentials are shifted by −105 mV at cell potential of 1.6 V, allowing stable cell parameters (capacitance, resistance) and reduction of corrosion products formation on positive steel collector after 120 hours floating. Phenanthrenequinone was grafted on activated carbon to get an additional faradaic contribution in buffer solutions (pH = 4.0 or 7.2). The three-electrode cell CVs show that the redox peaks of the phenanthrenequinone graft shift toward negative values when pH increases from 4 to 7. Electrical double-layer capacitors (EDLCs) based on activated carbons (AC) and traditional aqueous electrolytes, such as H 2 SO 4 and KOH, operate at low cell potential (up to ∼0.8 V), limiting their capability at industrial level. [1][2][3][4] In order to improve the energy (E = 1 2 CU 2 ), both capacitance (C) and cell potential (U) determined by the stability window of the electrolyte have to be optimized. In this context, it has been recently demonstrated that symmetric capacitors based on AC electrodes and salt aqueous electrolyte (0.5 mol L −1 Na 2 SO 4 ) exhibit excellent cyclability under galvanostatic charge/discharge up to 1.6 V. 5,6 . While using 1 mol L −1 Li 2 SO 4 and gold current collectors, excellent cycle life has been shown up to ∼1.9 V using galvanostatic charge/discharge. 7,8 Such high cell potential value is caused by a high over-potential for di-hydrogen evolution as a consequence of water reduction and OH − ions generation in the porosity of the negative AC electrode. 5,7 According to the Nernst equation (E red = −0.059 pH), the pH increase associated to OH − ions causes locally a shift of redox potential to lower values. Based on this fact, it has been recently demonstrated that the di-hydrogen evolution over-potential is higher in almost neutral electrolyte solutions (pH = 4-8) than in acidic ones, resulting in larger operating cell potential of asymmetric capacitors in the former media.9 From the foregoing, it makes sense to study in more details the influence of aqueous electrolyte pH on the electrochemical performance of AC/AC capacitors beyond only the cell potential.Besides, when shifting from gold to stainless steel current collectors in order to develop low cost AC/AC capacitors in 1 mol L −1 Li 2 SO 4 , constant capacitance and low cell resistance have been observed during potentiostatic floating at cell potential of 1.5 V, whil...

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“…B.1). This means that the formation of Ag 2 O is favored over AgCl at high pH values (also in agreement with the Pourbaix diagram for silver) and the more pronounced Ag 2 O shoulder in the LSV at pH 9 [38]. Therefore, pH 8 was a good compromise with the highest sensitivity, so we used this value in further experiments.…”

Section: Optimization Of the Phmentioning

confidence: 98%

Electrochemical detection of free chlorine at inkjet printed silver electrodes

Jović

Cortés‐Salazar

Lesch

et al. 2015

Journal of Electroanalytical Chemistry

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A low-cost, reliable and sensitive electrochemical method for free chlorine analysis in water using inkjet printed silver electrodes is presented. Free chlorine detection was based on linear sweep voltammetry (LSV) analysis of AgCl/Ag 2 O films formed over an inkjet printed silver electrode by the spontaneous reaction between silver and free chlorine species (i.e. HClO and ClO − ) present in solution. The formation of AgCl/Ag 2 O films was studied and characterized by high resolution scanning electron microscopy (HR SEM) and X-ray photoelectron spectroscopy (XPS) techniques. LSV characterization demonstrated a quantitative linear relationship between the amount of AgCl/Ag 2 O formed and the concentration of free chlorine in water within a range from 1 to 100 ppm. After optimization of several parameters (e.g. scan rate, reaction time, starting potential), lowest detectable free chlorine concentration was 0.4 ppm (by standard addition method), while the limit of detection (S/N = 3) was equal to 2 ppm, with a sensitivity of 30 μC/ppm. The validation of the proposed methodology was performed by comparison with the standard N,N-diethylparaphenylenediamine (DPD) method for analyzing swimming pool water samples. Finally, it was demonstrated that reproducible and disposable silver electrodes could be easily prepared by inkjet printing in a large scale and in any required geometry to fit on-line and onsite free chlorine analyses requirements.

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Pourbaix Diagrams for Multielement Systems

Cited by 36 publications

References 1 publication

Fe3O4/SiO2/TiO2 Core-Shell Nanoparticles as Catalyst for Ag(I) Ions

Fe3O4/SiO2/TiO2 Core-Shell Nanoparticles as Catalyst for Ag(I) Ions

Strategies to Improve the Performance of Carbon/Carbon Capacitors in Salt Aqueous Electrolytes

Electrochemical detection of free chlorine at inkjet printed silver electrodes

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