PS Ball Load Metal And Its Electrochemical Properties

Direct alcohol fuel cell (DAFC) possesses wide application in the portable equipment, field power and electric car etc., due to high energy efficiency, abundant sources, the free (or low) -pollution, the easy storage and transportation of the fuel. However, the low electrochemical activity and high cost of electrocatalysts are still one of the key issues hindering the commercial application of DAFC. Therefore, to improve the electrocatalytic activity and to decrease the loading mass of noble metals were effective routes to the commercial application of DAFC. Core-shell materials were researched by many scientists due to their feature in structure, size and composition. These materials had been widespread used in catalyst, sensor, drg delivery systems, composite and insulate materials ect.. In this article, polystyrene (PS) microspheres were produced by dispersion, emulsifier -free emulsion and emulsion polymerization methods. These microspheres were modified with -NO₂, -NH₂ and poly (diallyldimethylammonium choloride) (PDDA). Then these functional PS microspheres were used as templates to produce Au and Ni/Au hollow microspheres. These hollow microspheres were used as catalysis on positive elextrode. Their electrochemical properties were investigated in detail. The main results obtained in this paper were presented as follows:1. PS microspheres were produced by dispersion, emulsifier-free emulsion and emulsion polymerization methods. Their diameters successively were 2.0μm, 700 nm and 250 nm. And they have good dispersities.2. Ni and Ni/Au matels were loaded on surface of modified PS microspheres by chemical reduction, and use the same method, Au matel can be loaded on the surface of PS-PDDA. The surfaces of the matel shells which were reduced by NaBH4 were much rougher than those reduced by ethylene glycol. The Au shells on PS-PDDA were glossy. The surfaces of Ni/Au catalysis were getting rougher and rougher while incressing the ratio of Au. The hollow microspheres were produced by soaking the core-shell materials in N, N-Dimethylform amide (DMF). These soaking experiments were repeated seneral times, the PS core can be removed.3. Ni/Au hollow microspheres were used as catalysis on postive electrode in DAFC for the first time. The results indicated that Ni/Au hollow electrode had much higher electrocatalytic activities for alcohol oxidation than that of Ni hollow electrode. And the sortorder of their electrocatalytic activities in alkalic solution of glycerol, methyol and ethylene glycol was as follow: Ni/Au150 > Ni/Au50 > Ni. The electrocatalytic activities of NiAu were getting higher and higher while increasing the ratio og Au. Ni/Au composite catalysts had good abilities of anti-drug in methyol and n-propanol. Catalyst poisoning was not easy happend in a short time.4. Au hollow microspheres had good and stable electrocatalytic activities in alkalic solution of glycerol, methyol, ethanol, ethylene glycol, isopropanol and n-propanol.