title: Oxidative dissolution of silver nanoparticles by dioxygen: a kinetic and mechanistic study.
abstract: We have recently reported a kinetic and mechanistic study on oxidative dissolution of silver nanoparticles (AgNPs) by H(2)O(2). In the present study, the parameters that govern the dissolution of AgNPs by O(2) 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 (k(app)) of AgNPs (10±2.8 nm) by O(2) is about 100-fold slower than that of H(2)O(2). The reaction rate is first-order with respect to [Ag(0)], [O(2)], and [Tris](T), and inverse first-order with respect to [Ag(+)] (where [Ag(0)]=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 (O(2)(-)) 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 O(2) is proposed.
authors: 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. rickyho@hku.hk
authors: Chi-Ming
authors: CM
authors: Ho
authors: Chi-Kit
authors: CK
authors: Wong
authors: Sammi King-Woon
authors: SK
authors: Yau
authors: Chun-Nam
authors: CN
authors: Lok
authors: Chi-Ming
authors: CM
authors: Che