铂银合金的制备及其对甲醇电氧化反应的催化性能

Preparation of platinum-silver alloy nanoparticles and their catalytic performance in methanol electro-oxidation

采用一种无需使用任何有机表面活性剂或溶剂的方法,在熔融盐体系中制备了铂银纳米合金颗粒,考察了合金中元素银对碱性电解质中甲醇电氧化反应(MOR)的催化作用。透射电子显微镜表征结果显示,当前躯体铂银物质的量比为1时,可以得到组成为Pt52Ag48的合金纳米管。甲醇电氧化反应测试结果表明,具有干净表面的Pt52Ag48纳米管比常规的Pt黑具有更好的催化性能。Pt52Ag48合金纳米管的催化活性与其最大正扫电位密切相关,正扫电位从-1.0到0.5 V(vs.SCE),MOR峰值电流达到1.61 mA/μg Pt,是从-1.0到0.1V(vs.SCE)正扫电位的1.92倍。铂银合金表面层中的Ag元素主要通过在电化学循环中发生氧化还原反应来促进合金的MOR活性。研究结果可以为铂银合金在直接甲醇燃料电池(DMFC)中的应用提供理论支持。

Platinum-silver alloy nanoparticles(Pt xAgy NPs)were synthesized in a molten salt system without using any organic surfactants or solvents;the catalytic role of Ag in the methanol electrooxidation reaction(MOR)in alkaline electrolyte over Pt xAgy NPs was investigated.The TEM images suggest that Pt 52 Ag 48 nanotubes(NTs)can be obtained when the Pt/Ag ratio in the molten salt precursor reaches 1.The methanol electrooxidation reaction test results indicate that the Pt 52 Ag 48 NTs with a clean surface exhibits a much better catalytic performance than the conventional Pt black in MOR.Meanwhile,the catalytic activity of the Pt 52 Ag 48 NTs is greatly related to the positive potential limit;the peak current of MOR reaches 1.61 mA/μg Pt with a positive potential limit from-1.0 to 0.5 V(vs.SCE),which is 1.92 times higher than that with a positive potential limit from-1.0 to 0.1 V(vs.SCE).The Ag element in the surface layer of Pt x Ag y alloy may promote the MOR through a redox process during the electrochemical cycle.The insight shown in work should be beneficial to the application of Pt x Ag y alloy in the direct methanol fuel cells(DMFCs).