Direct Electrodeposition Of Au-Pt Bimetallic Nanoparticles And Its Properties

Metallic nanoparticles have been studied extensively because of their unique physical and chemical properties. Their applications branch out in multiple fields such as electrics, optics, catalysts, magnetic material, biotechnology, drug delivery ect.. In recent years, people have found that noble metal composite nanoparticles often exhibit peculiar properties that are absent in their individual constituent metallic nanoparticles. Noble metal composite nanoparticles, as attractive building blocks of advanced functional materials, have received enormous attention and developed into an increasingly important research area in nanomaterials science.In this paper, we firstly had explored a facile efficient route to synthesize Au-Pt alloy nanoparticles on indium tin oxide (ITO) electrode through direct electrochemical deposition. The gross volume of HAuCl4 and H2PtCl6 kept constant during the experiment but the molar ratio of the two were changed to prepare different nanoparticles. Scanning electron microscope(SEM), UV-Vis spectroscopy , X-ray diffraction(XRD), electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV) were used to characterize the properties of this prepared electrode. The results revealed that the prepared bimetallic nanoparticles were of alloy structure.At the same time, the correlations between the molar ratio of gold-platinum nanoparticles and the catalytic activity to formaldehyde, nitrite, hydrogen peroxide and glucose were also investigated. The results showed that the catalytic performance of Au-Pt alloy nanoparticles toward nitrite gained the utmost when the proportion of Au(III) to Pt(VI) reached 3:1. While the alloy nanoparticles displayed the best catalytic activity toward formaldehyde,hydrogen peroxide and glucose in the neutral medium when the molar ratio of Au(III) to Pt(VI) got 1:3. From the experimental results it can be concluded that the best molar ratio of gold-platinum nanoparticles for catalytic activity changed with different chemical substances. In optimal conditions, the calibration range of concentration was 0.0025～0.4775mM for nitrite, the calibration range of concentration was 4.88~505.48μg/g for formaldehyde, the calibration range of concentration was 0.02~2.04mM for glucose. For hydrogen peroxide the calibration range of concentration was 0.03~15.21μM at the relatively low polarization potential of 0.45V as the gold-platinum nanoparticles modified electrode can efficiently reduced the oxidative potential of hydrogen peroxide. The results illuminated that bimetallic nanoparticles were in favor of improving the catalytic capability of the electrode since there was synergetic activity between Au-NPs and Pt-NPs. The unique properties of bimetallic nanoparticles are expected to have further applications in the fields of catalyzer and sensor.