pH Dependent Redox Couple: An Illustration of the Nernst Equation

Walczak, Mary M.; Dryer, Deborah A.; Jacobson, Dana D.; Foss, Michele G.; Flynn, Nolan T.

doi:10.1021/ed074p1195

Cited by 125 publications

(81 citation statements)

References 3 publications

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“…(3)) as most of p-benzoquinones, involves the uptake of two H + and two e À to produce the corresponding hydroquinone DMBQH 2 [7,8]. The description in reaction (3) is really an oversimplification of a very complex mechanism that depends on the pH, [7,8] the presence of buffer in solution, [9] and even the electrode surface [10,11]. The reduction of [Ru(NH 3 ) 6 ] 3+ including the acid-catalyzed aquation that is observed when the complex is in the reduced form [Ru(NH 3 ) 6 ] 2+ , [12] requires one H + and one e À .…”

Section: Resultsmentioning

confidence: 99%

Removal of electroanalytical interferences using thermodynamic and kinetic effects induced by in situ electrogeneration of protons

Khalid

Álvarez

2009

Journal of Electroanalytical Chemistry

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Section: Resultsmentioning

confidence: 99%

Removal of electroanalytical interferences using thermodynamic and kinetic effects induced by in situ electrogeneration of protons

Khalid

Álvarez

2009

Journal of Electroanalytical Chemistry

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“…In comparison with anode potentials which was stable around −0.30 V, cathode potentials increased from 0.03 V at pH 8.0 to 0.13 V at pH Electrode potentials at 298 K exhibit a function of pH values according to Nernst equation as described in Eq. (4) [50]. A theoretically net change of potential with pH change was therefore shown in Eq.…”

Section: Effect Of Initial Phsmentioning

confidence: 99%

Evaluation of carbon-based materials in tubular biocathode microbial fuel cells in terms of hexavalent chromium reduction and electricity generation

Huang

Chai

Cheng

et al. 2011

Chemical Engineering Journal

114

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“…Growth of the Ag shell was then carried out at room temperature by reducing silver ions with HQ in the buffered solution of Au nanorods. Because the redox potential of hydroquinone varies with pH, [25] and H + is involved in the quinone/hydroquinone redox reaction, it is necessary to monitor the pH during the process. Thus, while at pH 7.4 or above, the HQ redox potential [18] is sufficient to overcome that of silver, both in the presence and in the absence ( …”

mentioning

confidence: 99%

Rapid Epitaxial Growth of Ag on Au Nanoparticles: From Au Nanorods to Core–Shell Au@Ag Octahedrons

Sánchez‐Iglesias

Carbó‐Argibay

Glaria

et al. 2010

Chemistry A European J

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The strongly shape-dependent optical properties of metal nanoparticles have motivated the rapid development of new and efficient strategies toward morphology control. [1][2][3] However, a highly efficient control over shape and size has been mainly achieved for gold. Therefore, an interesting route toward the production of other metal nanoparticles with tailored morphology would be the use of pre-formed gold nanocrystals as templates, on which other metals could be grown. This would allow not only a tight control over the growth, and morphology of the nanocrystals, but also an interesting enhancement of the functionality of such nanomaterials, [4][5][6][7][8] the properties of which would differ from those found in similar nanostructures made of the individual constituent metals. [4][5][6][7][8][9][10][11] In particular, various approaches have been developed to fabricate Au@Ag core-shell nanoparticles by the epitaxial growth of Ag on preformed Au nanoparticles, which were in general based on either chemical or photoinduced reduction processes. [5,9,10,12] The former often make use of a weak reducing agent, such as ascorbic acid or hydroxylamine, so that the reduction takes place exclusively on the surface of the metallic seed particles, which act as catalysts. [9,[13][14][15][16]34] However, this can only be achieved within a narrow pH range so that homogeneous nucleation of Ag nanoparticles in solution is avoided.Herein, we describe a simple and rapid method to grow silver on single-crystal Au nanorods, resulting in single-crystal core-shell Au@Ag nanoparticles with tailored morphology, ranging from nanorods all the way to spheres, through octahedrons, and thereby giving rise to a remarkable control over the optical response spanning the whole visible range and into the near IR.The growth method is based on the use of hydroquinone as reducing agent. Although the preparation of silver nanoparticles using hydroquinone has been previously reported, this typically resulted in a rather poor control over shape and size. [17,18] Additionally, hydroquinone has also been used to grow thin silver shells on gold nanoparticles as a means to amplify their scattering properties, but this was restricted to very thin shells on small spherical particles. [19,20] However, we demonstrate here that these processes can be utilized in a much more controlled manner, thus allowing exquisite morphology control. Based on our previous experience on the reshaping of single-crystal gold nanorods into octahedrons, [21] we decided to explore the coating of the same type of nanorods with silver, so as to tune the morphology of the resulting core-shell particles. Interestingly, we found that silver grows preferentially on the lateral facets of the Au nanorods, so that, indeed complete reshaping of the initial rods into Au@Ag octahedrons and even spheres was achieved, which might be related to the prior capping agent exchange from cetyltrimethylammonium bromide (CTAB) to methoxy-poly(ethylene glycol)-thiol (mPEG-SH). Detailed analysis of the op...

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pH Dependent Redox Couple: An Illustration of the Nernst Equation

Cited by 125 publications

References 3 publications

Removal of electroanalytical interferences using thermodynamic and kinetic effects induced by in situ electrogeneration of protons

Removal of electroanalytical interferences using thermodynamic and kinetic effects induced by in situ electrogeneration of protons

Evaluation of carbon-based materials in tubular biocathode microbial fuel cells in terms of hexavalent chromium reduction and electricity generation

Rapid Epitaxial Growth of Ag on Au Nanoparticles: From Au Nanorods to Core–Shell Au@Ag Octahedrons

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