Au-Pt Hollow Nanospheres With Different Quality Ratio Obtained At Different Process And Their Electrocatalytic Property For Small Organic Molecules Oxidation

Direct methanol fuel cell and direct formic acid fuel cell have the incomparable superiority relative to other fuel cell which have been paid attention by more and more people.In recent decades,people have done a lot of research about small organic moleccules direct fuel cell electrode catalyst materials and have achieved remarkable results.Platinum is also the best catalyst of small organic molecules direct fuel cell electrode reaction, but because platinum is resources poor and expensive, and easily to be poisoned by intermediates CO during the small organic molecules oxidation, stalling its practical process seriously. Researchers have been trying to reduce the amount of Pt in order to reduce the costs, and they trying to enhance its resistance to CO poisoning ability to improve the catalytic activity and stability.Metal nanomaterials have large surface area and high catalytic activity. But the large surface area can lead to reunite inactivation easily. Hollow structure of metal nanomaterials have porous shell and constructed by multidimensional, multilevel atom cluster. they are not only have the lower density, bigger specific surface area, can reduce the use amount of metal in order to reduce the costs, but also have a stable structure, difficult to reunite, good monodispersity and have more excellent catalytic performance, It is a new type catalyst materials of small organic molecule fuel cell electrode. This paper prepared more platinum less gold platinum-gold hollow nanospheres [(Pt-Au)HN] with different R ratio of amount of substance in two ways. The first way is add HAuCl4 and H2PtCl6 at the same time, the second way is add HAuCl4 and H2PtCl6 successively, discussing the differences of structure, composition and influence on the catalytic activity in this two ways. This paper also prepared more gold less platinum gold-platinum hollow nanospheres [(Au-Pt)HN] with different r ratio of amount of substance by adding HAuCl4 and H2PtCl6 at the same time, discussing the catalytic performance for C1 small organic molecules of gold-platinum hollow nanospheres with different r ratio. Providing experiment basis for prepared the higher cost performance platinum-gold hollow nanospheres.1. Preparing more platinum less gold (Pt-Au)HN with different R ratio in two ways.The first way is add HAuCl4 and H2PtCl6 at the same time, the second way is add HAuCl4 and H2PtCl6 successively.2. Preparing more gold less platinum (Au-Pt)HN with different r ratio by adding HAuCl4 and H2PtCl6 at the same time.3. Scanning electron microscopy (SEM), transmission electron microscope (TE M), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were applied to characterize the morph ology, composition and structure, The resultsshowed that:(1) The (Pt-Au)HN synthetised in two ways and (Au-Pt)HN synthetised by addi ng HAuCl4 and H2PtCl6 at the same time were hollow spherical structure.They have uniform size, good dispersibility. The spherical shell were porous, bulldin g by multi-dimensional and multi-level gold, platinum compound atomic cluster; the difference was that by the first way the surface of (Pt-Au)HN was rough, maybe i t was formed in the way of the island of gold method, so the surface of hollow nan ospheres like a litchi shell.and by the second way the surface of (Pt-Au)HN was smooth,that maybe the outermost layer was covered by platinum.so the surface of hollow nanospheres like a longans shell.(2) The Au and Pt inside the (Pt-Au)HN shell didn't form alloy or intermetallic comp ound. They were composited by Platinum and gold atoms cluster, and residual selen ium were inside the shell,it was not easy to eliminate by chemical method, but it could be done by electrochemical method.(3)In this two different ways the added Pt could not all be synthetised in (Pt-Au)HN, but the amount of added Pt could affect the contents of Pt in the (Pt-Au)HN directly. The added Pt in second way was much easier synthetized in (Pt-Au)HN than the first way.(4) When we added HAuCl4 and H2PtCl6 at the same time, no matter the (Pt-Au)HN with different R ratio or (Au-Pt)HN with different r ratio, the Pt in the s urface and inlayer of the shell was less than Au. But the proportion of Pt in t he surface is higher than that in inlayer; and when we added HAuCl4 and H2P tCl6 successively, the Pt was more than Au in the surface and Pt was lessthan Au in the inlayer.4. Using different (Pt-Au)HN modified glassy carbon (GC) electrode[(Pt-Au)HN/GC], researching their electrocatalysis oxidation performance for small organic molecule, the result shows that:(1) By adding HAuCl4 and H2PtCl6 at the same time, in acid medium, (Pt-Au) HN/GC has no electrocatalysis oxidation activity for Methanol; when R=1, (Pt-Au)HN/GC has the best electrocatalysis oxidation activity for Methanol in alkal ine medium and formic acid.(2) By adding HAuCl4 and HaPtCl6 successively, in acid medium, (Pt-Au)HN/G C has no electrocatalysis oxidation activity for Methanol when R?2, but when R?3 (Pt-Au)HN/GC appear electrocatalysis oxidation activity for Methanol; in alkaline medium, (Pt-Au)HN/GC have the best electrocatalysis oxidation activity when R=1. Whatever in acid medium or alkaline medium, the (Pt-Au)HN, synthetised b y the sencond way, has higher electrocatalysis oxidation activity for C1 smallor ganic molecules than the first way, it can save more Pt and have higher costp erformance.5. Using (Au-Pt)HN with different r ratio modified glassy carbon (GC) electrode [(Au-Pt)HN/GC], testing their electrocatalysis oxidation performance for smallorg anic molecule.it shows that:there was no electrocatalysis oxidation activity for Methanol in acid medium, and it has the best electrocatalysis oxidation activity for Methanol in alkaline medium and formic acid when r=20:1.