Oxidative Dissolution of Silver Nanoparticles by Dioxygen: A Kinetic and Mechanistic Study |
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| Authors: | Dr Chi‐Ming Ho Chi‐Kit Wong Dr Sammi King‐Woon Yau Dr Chun‐Nam Lok Prof Chi‐Ming Che |
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| Institution: | Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong (China), Fax: (+852)?2857‐1586 |
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| Abstract: | We have recently reported a kinetic and mechanistic study on oxidative dissolution of silver nanoparticles (AgNPs) by H2O2. In the present study, the parameters that govern the dissolution of AgNPs by O2 were revealed by using UV/Vis spectrophotometry. Under the same reaction conditions (Tris‐HOAc, pH 8.5, I=0.1 M at 25 °C) the apparent dissolution rate (kapp) of AgNPs (10±2.8 nm) by O2 is about 100‐fold slower than that of H2O2. The reaction rate is first‐order with respect to Ag0], O2], and Tris]T, and inverse first‐order with respect to Ag+] (where Ag0]=total concentration of Ag metal and Tris]T=total concentration of Tris). The rate constant is dependent on the size of AgNPs. No free superoxide (O2?) and hydroxyl radical (?OH) were detected by trapping experiments. On the basis of kinetic and trapping experiments, an amine‐activated pathway for the oxidation of AgNPs by O2 is proposed. |
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| Keywords: | kinetics nanoparticles oxidation oxygen silver |
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