Effect of Nonionic Surfactants on the Kinetics of Disproportion of Copper Sulfide Nanoparticles in the Aqueous Sols
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- 作者：Roshan H. Kore ; Jaideep S. Kulkarni ; and Santosh K. Haram
- 刊名：Chemistry of Materials
- 出版年：2001
- 出版时间：May 2001
- 年：2001
- 卷：13
- 期：5
- 页码：1789 - 1793
- 全文大小：79K
- 年卷期：v.13,no.5(May 2001)
- ISSN：1520-5002
文摘
The effect of nonionic surfactants on the disproportion kinetics of copper sulfide nanoparticles (aqueous sols) from the golden brown, copper-rich phase (Q-Cu2S) to the greencovellite phase (Q-CuS) has been presented. The transformation follows a first-order ratelaw. There is a substantial decrease in the rate of transformation in the presence of nonionicsurfactants, viz. TX-100, NP-9.5, and NP-40. An attempt has been made to explain thephenomenon based on a surface state catalyzed transformation that is sensitive to theadsorption. The surface coverage (
), estimated from the dependence of the rate constanton surfactant concentration, fitted the Langmuir adsorption isotherm. From these, theequilibrium constants and standard Gibbs free energy change of adsorption 
havebeen estimated.
), estimated from the dependence of the rate constanton surfactant concentration, fitted the Langmuir adsorption isotherm. From these, theequilibrium constants and standard Gibbs free energy change of adsorption havebeen estimated.