Abstract
In this study, the dumbbell-like Pt-Fe3O4 nanoparticle was prepared by using Pt nanoparticle with different sizes as the seeding nanoparticles. The 3, 6, and 13 nm of Pt nanoparticles were obtained by using Pt(acac)2 and oleylamine as the precursor and reducing agent, respectively. In addition, the different sizes of PT nanoparticles can be obtained by controlling the amount of reducing agent and synthesisis temperature from 140-180ºC. Using different sizes of Pt nanoparticles in the presence of iron-oleate, the different sizes of dumbbell-like Pt-Fe3O4 nanoparticle were successfully fabricated by tuning the ratios of Pt and iron-oleate. The synthesized Pt and Pt-Fe3O4 were characterized by TEM, XRD, TGA, ICP-AES, SQUID. The Pt showed better electron transfer ability. Pt and Pt-Fe3O4 were dispersed on graphite electrode to fabricate the amperomertic biosensor for sensing dopamine，the Pt-Fe3O4 electrode is linearly dependence on dopamine concentration in the range of 20-850,15-850 and 35-850 □M receptively, and the Pt-Fe3O4 electrode were 15-850,25-850,10-850 □M receptively. The detection limits of Pt were 7.49,7.36 and 8 □M receptively, and Pt-Fe3O4 were 7.22,6.14 and 0.13 □M receptively. In addition, the Pt-Fe3O4 shows better current value of signal intensity, linear range and more lower detection limits when compared Pt nanoparticles, clearly showing the application potential on biosensing and catalytic activity.