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Since the discovery of carbon nanotubes (CNTs) since, because of their excellent high specific surface area, high mechanical strength, fast electron transport properties and chemical stability, in all disciplines research fields are widely used, is a catalyst carrier with great potential . Meanwhile, the metal nanoparticles as small particle size, surface area, more than the number of surface atoms, unsaturated ligand atom to the surface forming a large number of dangling bond and an unsaturated bond, it has a high catalytic activity and the respective field has great potential to become an emerging catalysts. In recent years, the field of fuel cells and electrochemical sensors, the carbon supported metal nanoparticle composite material to cause concern, because the geometry between the two special effect and electronic effect in improving the electrochemical performance has demonstrated a great deal of superiority; the nanoparticle composition, size, dispersion, morphology and affects the composite material structures are a key factor catalytic activity. Based on this, mainly carbon-supported platinum Gold Nanoparticles and Its Application in fuel cells and electrochemical sensors for applications in the field of research, made some valuable results. Specific research are as follows: 1, the first method using mixed acid immersion into the functionalized MWCNTs, while reducing the two metals with ethylene glycol precursor prepared a series of Pt / Au molar ratio of different catalysts PtAu / MWCNTs; followed by change the order of deposition of the metal, i.e. the first deposited on MWCNTs redeposition Pt Au Nanoparticles Nanoparticles prepared Au @ Pt / MWCNTs nanocomposites (WPtAu = 20%, and the Pt / Au are 4:1 molar ratio) . XRD and TEM prove, MWCNTs did succeed on the load on the platinum gold nanoparticles, and the particles have an average diameter of about 4.0 nm. Methanol Electrocatalytic Oxidation experiments showed that: catalysts of different composition, when the Pt / Au molar ratio of 4:1, the best performance of the catalyst, indicating that adding an appropriate amount of Au nanoparticles can greatly enhance the catalytic ability; also found Au @ Pt (1:4) / MWCNTs catalytic performance was better than PtAu (4:1) / MWCNTs, the structure of the catalytic activity of the catalyst has a great influence. 2, sodium borohydride (NaBH4) as a reducing agent, sodium citrate as stabilizer while reducing chloroplatinic acid (H 2 PtCl 6 · 6H 2 < / sub> O) and chlorine auric acid (HAuCl 4 · 3H 2 O), was successfully prepared MWCNTs load PtAu-alloy nanoparticles composites PtAu-alloy/MWCNTs . With TEM, XPS and XRD its morphology and composition were characterized, the results show that, MWCNTs successfully load a platinum gold nanoparticles, with an average diameter of about 3.5 nm, narrow distribution range; and particles well dispersed and evenly distributed without agglomeration. Under acidic conditions, the electrocatalytic oxidation of formic acid experiments showed that: with Pt / MWCNTs compared, PtAu-alloy/MWCNTs electrocatalytic formic performance has been significantly improved, formic acid electrooxidation onset potential (-0.05 V) negative shift Oxidation occurs mainly in the low potential range (-0.05 V 0.65 V), a higher current density (3.12 mA / cm 2 ), good stability and good resistance to poisoning, catalyst for a fuel cell is expected to be widely used. Meanwhile, on the Au composite electro-catalytic role of formic acid, we use CO stripping voltammetry was carried out a preliminary study and discussion. 3, the use of ethylene glycol in order to restore law namely: ethylene glycol as a reducing agent, sodium citrate as stabilizer, has restored H 2 PtCl 6 · 6H < sub> 2 O and HAuCl 4 · 3H 2 O metal precursor, successfully prepared MWCNTs supported platinum gold nanoparticles Pt @ Au / MWCNTs composite materials. By TEM and XPS respectively, of its morphology and composition were characterized, the results showed that: MWCNTs successful load of gold nanoparticles of platinum, platinum, gold particles have an average particle size of about 4.0 nm, narrow distribution range; and the particle distribution, without agglomeration. And the effects of Pt @ Au / MWCNTs modified glassy carbon electrode for dopamine (DA) of the electro-catalytic properties, experiments show that: Pt @ Au / MWCNTs the DA has a good electrocatalytic properties, sensitivity up to 1.16 mA cm -2 (mmol / L) -1 , ceiling linear detection range up to 120μmol / L, the detection limit was 8.0 × 10 -8 mol / L, and biological there are a lot of ascorbic acid in vivo (AA) has a good anti-jamming capability. The material has a high sensitivity for the detection of DA, wide linear range, low detection limit, good stability and reproducibility and good. This research work for the detection of dopamine provides a simple and practical method, so Pt @ Au / MWCNTs composite is expected to detect biological samples have been promoted and applied.
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