CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology , Zhongguancun, Beiyitiao No. 11, Beijing, 100190, P. R. China.
Langmuir. 2011 Mar 15;27(6):2796-803. doi: 10.1021/la104566e. Epub 2011 Feb 18.
The island growth mode of Pt was employed to guide the forma-tion of PdPt alloy nanodots on gold nanorods (Au@PdPt NRs). Well-defined alloy nanodots, with tunable Pd/Pt ratios from 0.2 to 5, distribute homogeneously on the surface of the Au NR. Formation of nanodots shell leads to the red-shift and broadening of the longitudinal surface plasmon resonance (LSPR) band of the Au NRs. The Au@PdPt alloy NRs exhibit catalytic activity toward oxidation of often-used chromogenic substrates by dissolved oxygen under mild conditions, suggesting a new type of oxidase mimics. Composition dependence catalytic activity is observed for the oxidation of ascorbic acid (AA) and 3,3',5,5'-tetramethylbenzidine (TMB) and for the reduction of p-nitrophenol. For AA and TMB, catalytic activity enhances quickly at lower Pd/Pt ratios and tends to saturate at higher Pd/Pt ratios. For p-nitrophenol reduction, catalytic activity shows a nice linear relationship with Pd/Pt ratio owing to much higher catalytic activity of Pd. In conclusion, proper alloying of Pd and Pt presents an effective route to tailor the catalytic activity. Interesting, alloy nanodots can also catalyze the oxidation of Fe (II) to Fe (III) by dissolved oxygen. Thus, based on the competitive oxidation of TMB and Fe (II), selective detection of the latter can be achieved.
采用岛状生长模式引导钯铂合金纳米点在金纳米棒（Au@PdPtNRs）上形成。具有可调钯/铂比（0.2 至 5）的均匀分布的合金纳米点均匀地分布在 AuNR 的表面上。纳米点壳的形成导致 AuNR 的纵向表面等离子体共振（LSPR）带的红移和展宽。Au@PdPt 合金 NRs 在温和条件下对溶解氧氧化常用显色底物表现出催化活性，表明其为新型氧化酶模拟物。在氧化 AA 和 TMB 以及还原对硝基苯酚时，观察到了组成依赖性的催化活性。对于 AA 和 TMB，在较低的 Pd/Pt 比下，催化活性迅速增强，并在较高的 Pd/Pt 比下趋于饱和。对于对硝基苯酚的还原，由于 Pd 的催化活性高，催化活性与 Pd/Pt 比呈良好的线性关系。总之，Pd 和 Pt 的适当合金化提供了一种有效调节催化活性的途径。有趣的是，合金纳米点还可以通过溶解氧催化 Fe（II）氧化为 Fe（III）。因此，基于 TMB 和 Fe（II）的竞争氧化，可以实现对后者的选择性检测。
