Andreas H A, Birss V I
Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
J Phys Chem B. 2005 Mar 10;109(9):3743-50. doi: 10.1021/jp045811u.
Identification of the species formed during the in situ reduction of hexachloroplatinic acid by sodium ethoxide, forming a Pt sol, is made. The solution phase is shown to consist of suspended metallic Pt nanoparticles (1-3 nm in diameter), acetaldehyde, and a Pt(II) species, identified by NMR and X-ray adsorption near-edge spectroscopy (XANES) to be NaPtCl3(C2H4), a sodium analogue of Zeise's salt [KPtCl3(C2H4)]. The NaPtCl3(C2H4) product exhibits greater stability in both ethanol and air than the conventional Zeise's salt, providing a means of storing the useful Zeise's anion [PtCl3(C2H4)-]. Electrochemistry, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses have shown that the precipitate phase formed during the synthesis is composed solely of Pt particles approximately 6 nm in diameter and NaCl. Thermal gravimetric analysis/differential scanning calorimetry (TGA/DSC) showed that the color of the precipitate is an accurate gauge of the ratio of Pt to NaCl, with the lightest to darkest precipitates containing from 1% to 40% nanoparticulate Pt by mass, respectively. A comprehensive characterization of both phases formed has allowed us to propose a mechanism for the conversion of hexachloroplatinic acid to Pt nanoparticles.
对乙醇钠原位还原氯铂酸形成铂溶胶过程中所形成的物种进行了鉴定。结果表明，溶液相由悬浮的金属铂纳米颗粒（直径1 - 3纳米）、乙醛和一种铂（II）物种组成，通过核磁共振（NMR）和X射线吸收近边光谱（XANES）鉴定该铂（II）物种为NaPtCl3(C2H4)，它是蔡斯盐[KPtCl3(C2H4)]的钠类似物。与传统的蔡斯盐相比，NaPtCl3(C2H4)产物在乙醇和空气中都表现出更高的稳定性，为储存有用的蔡斯阴离子[PtCl3(C2H4)-]提供了一种方法。电化学、X射线衍射（XRD）和透射电子显微镜（TEM）分析表明，合成过程中形成的沉淀相仅由直径约6纳米的铂颗粒和氯化钠组成。热重分析/差示扫描量热法（TGA/DSC）表明，沉淀的颜色是铂与氯化钠比例的准确指标，颜色最浅到最深的沉淀中纳米颗粒铂的质量分数分别为1%至40%。对所形成的两个相的全面表征使我们能够提出氯铂酸转化为铂纳米颗粒的机制。
