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Quantitative Study of Electrochemical Reduction of Ag+ to Ag Nanoparticles in Aqueous Solutions by a Plasma Cathode.

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Title: Quantitative Study of Electrochemical Reduction of Ag+ to Ag Nanoparticles in Aqueous Solutions by a Plasma Cathode.
Authors: Ghosh, S.1, Hawtof, R.1, Rumbach, P.2, Go, D. B.2, Akolkar, R.3, Sankaran, R. M.1 mohan@case.edu
Source: Journal of The Electrochemical Society. 2017, Vol. 164 Issue 13, pD818-D824. 7p.
Subjects: Silver nanoparticles, Aqueous solutions
Abstract: Replacing the solid metal cathode in an electrolytic cell with a plasma (gas discharge) allows the reduction of metal salt solutions to metal nanoparticles. Here, we apply gravimetric analysis to quantify the charge transfer (faradaic) efficiency of this reduction process and understand reaction pathways at the plasma-liquid interface. Silver powder synthesized from aqueous solutions of silver nitrate is collected and the weight is compared to the theoretical amount of silver obtained by applying Faraday's law of electrolysis. We find that the faradaic efficiencies are near 100% when the initial silver nitrate concentration is large (>100 mM), but are much less than 100% at low salt concentrations (<15 mM) or at high applied currents (>6 mA). These results are explained in terms of reaction kinetics involving solvated electrons and two important reactions: the reduction of silver ions (Ag+) and the second order recombination of solvated electrons which releases hydrogen gas. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:Replacing the solid metal cathode in an electrolytic cell with a plasma (gas discharge) allows the reduction of metal salt solutions to metal nanoparticles. Here, we apply gravimetric analysis to quantify the charge transfer (faradaic) efficiency of this reduction process and understand reaction pathways at the plasma-liquid interface. Silver powder synthesized from aqueous solutions of silver nitrate is collected and the weight is compared to the theoretical amount of silver obtained by applying Faraday's law of electrolysis. We find that the faradaic efficiencies are near 100% when the initial silver nitrate concentration is large (>100 mM), but are much less than 100% at low salt concentrations (<15 mM) or at high applied currents (>6 mA). These results are explained in terms of reaction kinetics involving solvated electrons and two important reactions: the reduction of silver ions (Ag+) and the second order recombination of solvated electrons which releases hydrogen gas. [ABSTRACT FROM AUTHOR]
ISSN:00134651
DOI:10.1149/2.0541713jes