Preparation And Electrocatalysis Of Pt Based Alloy One Dimensional Nanostructure Based On Insulin

Nanostructured platinum is widely used in many technical applications, including as an electrocatalyst in fuel cells. However, several challenges such as high cost and limited supply, still hinder its commercialization. Pt-based alloy attracted much attention, because it can not only reduce the platinum consume, but also improve catalytic activity and prolong the life time of catalyst.In this paper, insulin amyloid fibrils(INSAFs) were used as templates to control the synthesis of Pt-Pd alloy nanoparticle chains and Pt-Rh alloy nanowires. The morphology and the structure of the samples were characterized by Transmission Electron Microscopy(TEM), X-Ray Diffraction(XRD), Inductively Coupled Plasma-Optical Emission Spectrometry(ICP-OES), X-Ray Photoelectron Spectroscopy(XPS). The catalytic properties of the samples were studied by CO catalytic oxidation and electrochemical techniques. The details and results are summarized as follows:Based on the assistance of INSAFs, Pt-Pd alloy nanoparticle chains with even particle size of 3.0 nm and length up to several micrometers were successfully synthesized. All the particles grew along the axial direction of INSAFs. The influences of the molar ration of Pt Cl4 and Pd Cl2, reagent concentrations and reductants on the growth of Pt-Pd alloy nanoparticle chains were studied. Pt-Pd alloy nanoparticle chains showed obvious catalytic activity for CO oxidation when the temperature was raised to 80℃, which is 80℃ lower than that of commercial Pt black, showing a higher sensitivity.Pt-Rh alloy nanowires with diameter of 2.0~3.0 nm and length up to micron were fabricated by using INSAFs as a control template. The influences of the molar ration of Pt Cl4 and Rh Cl3, reagent concentrations and reductants on the growth of Pt-Rh alloy nanowires were also studied. A facile NH3-processed protocol was employed to remove the INSAFs templates, and the pure Pt-Rh alloy nanowires were obtained. Cyclic voltammetry tests reveal that the electrochemical active surface area(ECSA) of the template-removing Pt-Rh alloy nanowires(79.2 m2/gPt-Rh) is found 15.6% higher than that of commercial Pt/C catalyst(68.5 m2/gPt). The specific activity of Pt-Rh alloy catalyst in methanol oxidation reaction is 0.57 m A/cm2, 58% higher than that of the commercial Pt/C catalysts(0.36 m A/cm2), indicating a higher catalytic activity for methanol oxidation. Meanwhile, the If/Ib ratio of Pt-Rh nanowires is 1.78, showing a strong ability of resistance to CO poisoning. Chronoamperometry tests reveal that the synthesized Pt-Rh alloy nanowires maintain a better electrochemical durability than the commercial Pt/C catalysts.